Skip to main content
NCBI home page
JACS Au logoLink to JACS Au
. 2021 Feb 19;1(3):344–353. doi: 10.1021/jacsau.0c00100

Catalyst-Free Spontaneous Polymerization with 100% Atom Economy: Facile Synthesis of Photoresponsive Polysulfonates with Multifunctionalities

Xiaolin Liu †, Xin Liang ‡, Yubing Hu †, Lei Han †,‡,*, Qing Qu ∥, Dongming Liu ⊥, Jing Guo ∇, Zebing Zeng ∇, Haotian Bai †, Ryan T K Kwok †,§, Anjun Qin ⊥, Jacky W Y Lam †,§,*, Ben Zhong Tang †,§,⊥,#,*
PMCID: PMC8395608  PMID: 34467298

Abstract

graphic file with name au0c00100_0007.jpg

Photoresponsive polymers have attracted extensive attention due to their tunable functionalities and advanced applications; thus, it is significant to develop facile in situ synthesis strategies, extend polymers family, and establish various applications for photoresponsive polymers. Herein, we develop a catalyst-free spontaneous polymerization of dihaloalkynes and disulfonic acids without photosensitive monomers for the in situ synthesis of photoresponsive polysulfonates at room temperature in air with 100% atom economy in high yields. The resulting polysulfonates could undergo visible photodegradation with strong photoacid generation, leading to various applications including dual-emissive or 3D photopatterning, and practical broad-spectrum antibacterial activity. The halogen-rich polysulfonates also exhibit a high and photoswitched refractive index and could undergo efficient postfunctionalizations to further expand the variety and functionality of photoresponsive heteroatom-containing polyesters.

Keywords: catalyst-free polymerization, photoresponsive materials, photoacid generator, photopatterning, bacteria killing

Introduction

Light is the source of life, which provides energy for all living organisms1 and inspires scientists to explore photoresponsive materials for real-world applications.2,3 Different from other commonly used stimuli such as force, pH, temperature, electricity, and polarity, light can be used as a remote and noninvasive trigger with high spatiotemporal resolution and without introducing additional reagents,4,5 making the photoresponsive materials excellent candidates for diverse advanced applications including as optoelectronic devices and in the biomedical field.6−9 The photoacid generator is one of the most interesting photoresponsive materials with many potential applications such as in (bio)pattern generation, as an antimicrobial, and in tissue engineering.10 Although a wide range of photoacid generators have been reported, there is still room for improvement. For example, some systems generate only weak acid,11 some photoacid generating processes are invisible,12 and previous reported photoacid generators are generally small molecules with poor processability,13 all of which limit their applications.

Among the photoresponsive materials, polymer-based materials show unusual advantages because of their good processability and film-forming ability. However, the research progress of photoresponsive polymers is unsatisfactory because of the synthetic difficulty. They are generally synthesized from photosensitive monomers,14,15 which are carefully designed and expensive with limited variety. The lack of powerful polymerization methodology makes it difficult to incorporate diverse functional moieties into the polymer architecture and thus impede the development of photoresponsive polymers. Therefore, it is highly desirable to develop facile polymerization methodologies for the in situ generation of photoresponsive polymers from simple starting materials. Moreover, the incorporation of fluorescent moieties, especially aggregation-induced emission (AIE) luminophores, into the photoresponsive polymers is anticipated to make the photoresponse processes visible and further expand their applications. Considering that the sulfonate ester group is photoresponsive,16−19 polysulfonates could possibly undergo photodegradation readily with photoacid generation. Traditionally, polysulfonates are synthesized through interfacial polycondensations of aromatic sulfonyl chlorides and phenols. Unfortunately, this method is not suitable for multifarious monomers and the polymeric products obtained often show large polydispersity with low atom economy.20,21

In 2017, Sharpless et al. reported an efficient sulfur(VI) fluoride exchange (SuFEx) click reaction for the synthesis of polysulfonates,22−24 which is a big step forward and opens an avenue for the simple synthesis of polysulfonates.25 However, a catalyst, expensive monomers, heating, dry conditions, and inert gas protection are required in the SuFEx reaction, and the atom economy still needs to be improved due to the release of bulky byproduct. Herein, we developed a catalyst-free spontaneous polymerization from the organic reaction of commercially available disulfonic acids and readily accessible dihaloalkynes26 for the in situ generation of photoresponsive polysulfonates in excellent yields and high molecular weights (Figure 1a). This catalyst-free polymerization was conducted at room temperature in air in a short reaction time with 100% atom economy. The resulting polysulfonates could undergo photodegradation accompanied by efficient photoacid generation and visible fluorescence change, which endowed them with multifunctionalities, including dual-emissive or 3D fluorescent photopatterning and broad-spectrum irreversible antibacterial activity. The halogen-rich polysulfonates exhibit a high and photoswitchable refractive index and could undergo efficient postfunctionalizations to further enrich the variety and functionality of photoresponsive heteroatom-containing polyesters.

Figure 1.

Figure 1

Open in a new tab

(a) Catalyst-free polymerization of disulfonic acids and dihaloalkynes to photoresponsive polysulfonates. (b, c) In situ three-dimensional FT-IR spectra of the peaks at 1604 cm–1 (b) and 1391 cm–1 (c) during polymerization conducted at room temperature.

Results and Discussion

Polymerization

Monomers used in this work are easily available. Disulfonic acids 2a–2c were purchased commercially, were inexpensive, and were used without further purification. Dihaloalkynes 1a–1e were easily synthesized in high yields according to the previously reported procedures (Schemes S1 and S2).27−30 All the polymerizations were conducted under air at room temperature in a one-pot catalyst-free manner without generating any byproduct.

To obtain soluble polysulfonates in high yields with high molecular weights, we systematically investigated the polymerization conditions using 1a and 2a as monomers. The solvent, concentration, and reaction time were carefully investigated (Table 1). The effect of solvent on the polymerization was first investigated (Table 1, entries 1–3). Dichloromethane (DCM) is a good solvent for haloalkynes but is a poor solvent for sulfonic acids, while hexafluoro-2-propanol (HFIP) is a good solvent for sulfonic acids because of the strong hydrogen bonding interaction31 but is a poor solvent for haloalkynes. To achieve the best solving power for all monomers, HFIP/DCM mixtures with various volume fractions of HFIP and DCM were used for polymerization. As shown in Table 1, the best polymerization result was obtained in HFIP/DCM (v/v, 1/8), which gave a polymer with a weight-average molecular weight (Mw) of 13 800 in 88% yield (entry 3). A polymer with a higher molecular weight was obtained in a solvent mixture with a lesser HFIP fraction probably because it is a poor solvent for the resulting polymer. In addition, the monomer concentration (Table 1, entries 3–4) also played a crucial role for the polymerization. When the monomer concentration of 1a was increased from 0.1 to 0.2 M, a polymer with a higher Mw was obtained in a higher yield (entry 4). However, further increasing the concentration of 1a to 0.4 M led to a sharp decrease in both Mw and yield as the monomers were not completely dissolved. To reveal the kinetic of this polymerization, in situ IR spectroscopy was used to monitor the formation of polysulfonates. The reaction progress of monomers 1a and 2a was monitored in air at room temperature. It is obvious that two new peaks corresponding to C–O and C=C stretching vibrations emerged at ∼1391 and 1604 cm–1 in the spectra of the resulting poymer (Figure 1b and c), and their intensity reached saturation within 2 h, suggesting the fast rate and high efficiency of this reaction. Thus, a time of 2 h was adopted as the optimal reaction time, since prolonging the reaction time to even 8 h did not lead to higher Mw and yield (Table 1, entries 4–6).

Table 1. Polymerization Results of Dihaloalkynes and Disulfonic Acidsa.

entry monomer HFIP:DCM [1] (M) yield (%) Mwd Mw/Mnd
1 1a/2a 1:1 0.10 90 5900 1.5
2 1a/2a 1:4 0.10 84 10 100 1.9
3 1a/2a 1:8 0.10 88 13 800 2.3
4 1a/2a 1:8 0.20 83 27 600 2.3
5b 1a/2a 1:8 0.20 83 29 900 2.4
6c 1a/2a 1:8 0.20 84 27 700 2.3
7 1b/2a 1:8 0.20 94 11 900 1.5
8 1c/2a 1:8 0.20 91 9500 1.3
9 1d/2a 1:8 0.20 80 12 800 1.7
10 1e/2a 1:8 0.20 88 11 500 2.3
11b 1a/2b 1:8 0.20 75 27 000 3.1
12b 1a/2c 1:8 0.20 69 16 200 1.9
Open in a new tab
a

Unless otherwise noted, polymerizations were carried out at room temperature in air with [1] = [2] for 2 h.

b

Reaction time was 4 h.

c

Reaction time was 8 h.

d

Estimated by GPC in THF on the basis of a linear polystyrene calibration.

Under the optimized polymerization conditions, different monomer combinations were employed to evaluate the robustness and universality of this polymerization route. As shown in Table 1, dihaloalkynes 1a–c with different halogen atoms all reacted efficiently with 2a to afford polysulfonates in excellent yields with high molecular weights (entries 4, 7, and 8). The polymerizations also proceeded well for fluorene-substituted haloalkyne 1d and spirobifluorene-substitued haloalkyne 1e with large steric and 2a (entries 9 and 10). Regarding the monomer scope of sulfonic acids, we found that all reacted efficiently with 1a to generate polysulfonates with excellent Mw in high yields, regardless of their rigidity, aromaticity, and bulkiness (entries 4, 11, and 12). All the obtained polysulfonates showed excellent solubility in commonly used organic solvents, such as DMF, DMSO, THF, DCM, and chloroform.

Structural Characterization

To gain insight into the structures of the halogen-rich polysulfonates, model compound 3 was prepared by reaction of haloalkyne 1a and p-toluenesulfonic acid under the same synthetic conditions for the polymerization (Scheme S3). Typical FT-IR, 1H NMR, and 13C NMR spectra of polymer P1a/2a, model compound 3, and their corresponding monomers 1a and 2a are provided in Figure S1. The C≡C stretching vibrations of 1a and O–H stretching vibrations of 2a occurred at 2194 and 3442 cm–1, respectively. These peaks were not observed in the spectra of 3 and P1a/2a. Meanwhile, new peaks associated with C=C and C–O appeared at 1604 and 1391 cm–1, respectively, indicating the successful occurrence of the polymerization. Similar observations were also found in the FT-IR spectra of other polymers (Figures S2 and S3).

The NMR spectra provided more detailed information about the polymer structures. The 1H NMR spectrum of P1a/2a displayed a new peak emerged at δ 6.47, corresponding to the vinyl proton at position “c” (Figure 2d). The 13C NMR analysis further verified the polymer structure (Figure 2e–h). The characteristic peaks of the C≡C resonances of 1a were not observed in the polymer spectrum. Instead, the carbon at position “c” resonated at δ 101.41. For all seven polysulfonates, the characteristic peaks of their vinyl protons absorbed at δ 6.30–6.75 and their 13C NMR spectra showed no C≡C carbon absorption peaks, confirming the successful synthesis of polymers with structures as shown in Figure 1a (Figures S7–S20).

Figure 2.

Figure 2

Open in a new tab

1H NMR spectra of (a) 2a in DMSO-d6 and (b) 1a; (c) model compound 3 and (d) P1a/2a in CD2Cl2. 13C NMR spectra of (e) 1a in DMSO-d6 and (f) 1a; (g) model compound 3 and (h) P1a/2a in CD2Cl2.

Polymerization Mechanism

Based on the mechanism of small molecules,26 we proposed a mechanism for the polymerization of disulfonic acids and dihaloalkynes (Scheme S4). The sulfonic acid could form hydrogen bonding with the typical hydrogen bonding donor HFIP (Figures S23 and S24). The formation of hydrogen bonding clusters not only increased the solubility of disulfonic acid monomers in the polymerization system but also increased the reactivity/acidity of sulfonic acid.26,31 The first step of the polymerization was the proton transfer from disulfonic acid to dihaloalkyne, generating the vinyl carbocation intermediate. Then the intermediate underwent nucleophilic attack by disulfonic acid to form the alkenyl sulfonate moiety. These processes were repeated following the same addition mechanism, eventually forming the resulting polysulfonates.

Photophysical Properties

The absorption and emission spectra of dilute THF solutions (40 μM) of the as-synthesized polysulfonates were shown in Figures S25 and S26. The emission of polysulfonates is easily tunable from 440 to 550 nm by polymerization using monomers with different electron density (Figure S26).

By incorporating tetraphenylethylene (TPE) into the polysulfonate skeleton, the resulting polymers P1a–c/2a, P1a/2b, and P1a/2c showed aggregation-enhanced emission. Taking P1a/2a as an example, its DCM solution emitted weakly at 502 nm. Upon addition of a nonpolar poor solvent, such as hexane, the emission became stronger gradually, accompanied by a slight blue-shift in emission maximum to 487 nm (Figures S27 and S28).

Photodegradation and Photoacid Generation

Some previous papers have reported that aryl sulfonate decomposes upon exposure to UV irradiation.16,18,32 This inspired us to investigate whether the polysulfonates synthesized in this work could readily undergo photodegradation. As shown in Figure 3a, white light irradiation (400–780 nm) of a THF solution of P1a/2a with an intensity of 500 mW/cm2 for 160 min exerted no change on the molecular weight of the polymer, suggestive of its superhigh stability. In contrast, when exposed to the THF solution (1 mg/mL) of P1a/2a to 365 nm UV irradiation with an intensity of 40 mW/cm2 for 160 min, the Mn of the polymer gradually decreased from 12.1 to 1.9 kDa. The Mn of the P1a/2a film also decreased to 4.3 kDa under the same irradiation conditions. To our surprise, the photodegradation of the polymer could be accelerated in the presence of water. In a H2O/THF mixture (v/v, 1/99), the Mn of P1a/2a decreased to 4.4 kDa within only 5 min and the polymer was completely degraded in 60 min. Dripping water on the P1a/2a film could also accelerate the photodegradation of the polymer.

Figure 3.

Figure 3

Open in a new tab

Photodegradation and photoacid generation of P1a/2a. (a) Change of molecular weight of P1a/2a (1 mg/mL) in THF, H2O/THF mixture (v/v, 1/99), thin film, or thin film with water at different irradiation time. (b) Change of pH of P1a/2a (1 mg/mL) in H2O/THF mixture (v/v, 1/99) at different irradiation time. (c) Emission spectra of P1a/2a (100 μM) suspension in THF/H2O mixture (v/v, 1/99) before and after UV irradiation. Excitation wavelength: 330 nm. Inset: corresponding fluorescent photographs of P1a/2a suspension taken under 365 nm UV irradiation. (d) Proposed mechanism of photodegradation.

The “on-water” photodegradation effect is possibly related to the formation of sulfonic acid. To study the acid generation during the photodegradation of P1a/2a, a pH assay was conducted in a H2O/THF mixture (v/v, 1/99) of P1a/2a (Figure 3b) using a pH meter for organic solvents equipped with a H+ ion sensitive glass electrode. The initial pH of the polymer solution was neutral and remained constant under strong white light irradiation (400–780 nm) with the intensity of 500 mW/cm2. However, the pH of the polymer solution showed a sharp decrease upon prolonged 365 nm UV irradiation with an intensity of 40 mW/cm2 and decreased from 7.1 to 0.3 within 20 min, suggesting the formation of a strong acid. P1b–1e/2a could all undergo photodegradation with strong photoacid generation as efficiently as P1a/2a (Figure S30 and Table S3), indicating that the halogen-containing polyslfonates were highly sensitive to UV irradiation, and the R1 groups did not show obvious influence on the photodegradation rate.

Interestingly, the photodegradation process could be visualized by naked eyes as the P1a/2a suspension in THF/H2O mixture (v/v, 1/99) underwent a significant change of the emission maximum value from 495 to 427 nm during the photodegradation (Figure 3c and Table S2). The large fluorescence color change is mainly due to the decrease of conjugation length.

In 1998, Scaiano et al. studied the photodegradation mechanism of sulfonate esters systematically and demonstrated radical formation during degradation using transient spectra.32 Based on the previous reported mechanism and our experimental results, we proposed a mechanism of photodegradation and photoacid generation (Figure 3d). In the electron paramagnetic resonance experiment at room temperature, the powder of P1a/2a exhibited a radical signal (g-factor = 2.0039) under UV irradiation in comparison with the radical silence property of the pristine polymer powder in the dark (Figure S31). Thus, the photodegradation was possibly initiated by a photoinduced homolytic S–O scission to generate a radical pair. Then the escaped sulfonyl radical 5 reacted with water to form the sulfonic acid product 8. This corresponds to the on-water effect of the photodegradation. The phenoxyl radical 4 was probably transformed to vinyl alcohol 6 and then underwent tautomerization to generate the α-haloacetophenone 7. To verify the proposed mechanism, matrix-assisted laser desorption/ionization-time-of-flight (MALDI-TOF) spectrum of the photodegradation product of model compound 3 was measured, which demonstrated the formation of sulfonic acid product (Figure S32). In the time-dependent photodegradation 1H NMR experiment (Figure S33), a new peak emerged at δ 2.29 and generally increased after UV irradiation, corresponding to the methyl group of p-toluenesulfonic acid. In addition, the 1H NMR spectra and 13C NMR spectra of the degradation product also confirmed the disappearance of the C=C double bond and the formation of keto groups (Figures S33 and S34).

Fluorescent Photopatterning and Light Refraction

The generation of complex fluorescent patterns by photolithography technique is of great significance in terms of optical writing and reading, anticounterfeiting applications, and biological sensing systems.33 Because of the excellent solubility and film-forming ability of the present polysulfonates, their uniform films without defects can be easily fabricated on silica wafers by a simple spin-coating technique. The photoresponsive behavior of the polysulfonates makes them excellent candidates for pattern generation. As shown in Figure 4a, under light irradiation from a mercury arc lamp (200–400 nm) in air for 40 min through a photomask, the polymer first underwent photodegradation and then subsequent photo-oxidation. Fluorescence of the exposed regions was completely quenched due to the photo-oxidation of the chromophores,34,35 while the emissive areas were protected by the mask and remained intact. Thus, two-dimensional fluorescent patterns were generated. Surprisingly, these patterns could also be clearly observed under room light (Figure 4a). By changing the shape and scale of the photomask, a photopattern in microscale could also be generated with high resolution and sharp edges (Figure 4b).

Figure 4.

Figure 4

Open in a new tab

Fluorescent photopatterning and light refraction of the photoresponsive polymer P1a/2a. (a) Process of the 2D fluorescent photopatterning (left) and photographs of the pattern under UV irradiation (middle) or room light (right). (b) Process of the 2D microscale fluorescent photopatterning (left), photograph of the pattern under UV irradiation (middle), and grayscale intensity profile of the area indicated by the white arrow (right). (c) Process of the dual-emissive photopatterning. (d) Images of the photomasks and photograph of the dual-emissive photopattern under UV irradiation. (e) 3D heart-shaped photopattern generation process and photographs taken under daylight or UV irradiation. (f) Microscopic photographs of the 2D (left) and 3D (middle) gridlike photopatterns taken under UV irradiation and 3D gridlike sample with a tilt angle observed under the bright field (right). (g) 3D AFM image of the 3D gridlike sample in a 10 μm square. (h) Wavelength-dependent refractive index of thin films of P1a/2a at different UV irradiation time. Excitation wavelength for fluorescent photographs: 365 nm.

The creation of highly ordered dual-emissive fluorescent patterns is meaningful but challenging. Previously reported methods either are time-consuming36 or require mixtures of different fluorescent materials.37,38 However, using only a single material for dual-emissive luminescent photopatterns is still rare. Considering that the fluorescence of P1a/2a blue-shifted under UV irradiation for a short time due to photodegradation and was photobleached under UV irradiation for long time, we tried to fabricate a dual-emissive fluorescent pattern using P1a/2a film. The polymer film was first irradiated with a mercury arc lamp (200–400 nm) through both photomask I and II for 40 min to induce photobleaching. Then mask I was removed and the film was further irradiated for 5 min through mask II to trigger photodegradation (Figure 4c). As a result, a fluorescent “earth” picture with green and blue emission was finally generated (Figure 4d).

Nature is an expert in fabricating micro- or nano-three-dimensional (3D) ordered structures, such as the superhydrophobic surface of the lotus leaf and the structural coloration of the insects and animals.39−41 Thus, 3D ordered patterns have attracted considerable research interest due to their special functionalities.42 As the polysulfonates are highly sensitive to UV irradiation, they are ideal materials for 3D fluorescent pattern fabrication. As shown in Figure 4e, after the polymer film was irradiated with 365 nm for 5 min through a heart-shaped mask, the irradiated part showed a blue-shifted fluorescence and remarkable change in the refractive index due to photodegradation. By dipping the film in methanol for a few seconds, the irradiated part was washed away completely because the irradiated polymers lost their mechanical property. The protected part, on the contrary, was intact. Finally, a 3D heart-shaped pattern was generated. By changing the scale and pattern of the photomask, a 3D fluorescent microarray could be fabricated in the same way (Figure 4f). The 3D structure could be observed by slightly slanting the microarray under the bright field of the microscope (Figure 4f, right). The height of the step was measured to be 75 nm by atomic force microscopy (AFM, Figure 4g). The facile, rapid, and precisely controllable fabrication of fluorescent 3D ordered structures demonstrated the promising future of polysulfonates in constructing biomimetic materials, functional interfaces, and cost-efficient photolithography materials.

The photoresponse behavior of these polysulfonates encouraged us to further explore whether their refractions are photoswitchable. Their initial refractive index (n) values were first measured (Figure S35 and Table S4). By incorporating different monomers into the polymer backbone, the polysulfonates P1a–d/2a showed high refractive indices ranging from 1.920 to 1.626 in the spectral range of 400–900 nm. It is worth noting that the n values of P1a/2a were 1.823 at 486.1 nm and 1.770 at 632.8 nm, which were higher than those of sapphire (1.776 at 486.1 nm and 1.766 at 632.8 nm) and much higher than those of commercially important optical polymers, such as polycarbonate (n486.1 = 1.600 and n632.8 = 1.581) and poly(methyl methacrylate) (n486.1 = 1.497 and n632.8 = 1.489).43 As shown in Figure 4h and Table S5, the n values of P1a/2a decreased gradually with prolonged irradiation time and the n difference (Δn) at 632.8 nm before and after light irradiation with a mercury arc lamp (200–400 nm) for 40 min could be as large as 0.1. The excellent tunability of the film refractivity by UV irradiation enables these polymers to find promising applications in optical data storage devices, gradient-index optics, and integrated photonic technology.44−48

Photoacid Generator for Broad-Spectrum Bacteria Killing

Controllable broad-spectrum bactericides and antibiotics are invaluable for modern healthcare-associated infections.49−53 The ability of generating strong photoacids of the polysulfonates motivates us to further explore their antibacterial performance as the pH value has a significant influence on the bacterial growth.54

In a preliminary experiment, the UV-triggered pH change of a bacteria resuspension containing P1a/2a was investigated and the pH was found to decrease from 6.7 to 2.3 after 365 nm UV irradiation for 30 min (Figure S36). It is worth noting that the pH change of P1a/2a in the bacteria resuspension was slower than that in the H2O/THF mixed solvent (Figure 3b), presumably due to the buffer capacity of the bacterial cytosol. Excitingly, under natural light, P1a/2a showed no toxicity to all the three bacteria species even at a concentration of 2 mg/mL (Figure S37), which facilitated the controllable bacteria killing in ordinary circumstances. According to the preliminary experiments (Figure S36–S38), 2 mg/mL P1a/2a solution and 30 min UV irradiation were adopted as experimental conditions in the subsequent experiments.

By virtue of the photoacid generation ability and hypotoxicity of P1a/2a, the antimicrobial activities of P1a/2a were subsequently evaluated to representative pathogenic bacteria (Gram-positive Staphylococcus aureus and Gram-negative Escherichia coli and Pseudomonas aeruginosa) by a traditional plate counting method. As shown in Figures 5a and S39, in the absence of P1a/2a, all three kinds of bacteria grew and reproduced smoothly on the agar plates in the dark or under UV irradiation. The dark toxicity of P1a/2a was inconspicuous on all bacteria. In the presence of both P1a/2a and UV irradiation, all three bacteria were killed effectively and no colony formation could be observed on the plates, implying the excellent broad-spectrum antibacterial effect of P1a/2a.

Figure 5.

Figure 5

Open in a new tab

Controllable broad-spectrum bacteria killing by photoacid generator P1a/2a. (a) Survival rates of E. coli, S. aureus (SA), and P. aeruginosa (PA) with/without treatment of P1a/2a (2 mg/mL) in the presence or absence of light irradiation at 365 nm (40 mW cm–2, 30 min). (b) Morphology change of bacteria upon diverse treatments observed by SEM. (c) Morphology change of bacteria upon diverse treatments observed by TEM. (d) Photographs of agar plates of E. coli, SA, and PA after 1 day and 15 days. (e) Two antimicrobial methods for practical applications. (f) Photographs of the agar plates from two antimicrobial methods.

To further confirm the bacteria killing effect of P1a/2a, we employed scanning electron microscopy (SEM) and transmission electron microscopy (TEM) to visualize the morphological changes of bacterial cells under P1a/2a treatment, with S. aureus, E. coli, and P. aeruginosa as representatives (Figure 5b and c). Without P1a/2a or UV irradiation, all kinds of bacteria showed their regular shape with well-defined borders and cell walls. When E. coli and P. aeruginosa were treated with P1a/2a and UV irradiation, obvious cell deformation, broken cells with the leakage of intracellular contents, and cell fragments were observed. S. aureus treated by P1a/2a and UV irradiation on the other hand, showed a rough surface and fissured cell wall.

Furthermore, the bacteria treated by P1a/2a and UV irradiation did not grow any more on agar plate after incubation at 37 °C for 15 days (Figure 5d), which demonstrated the 100% irreversible bacteria killing effect of P1a/2a.

The above data indicated that the as-synthesized polymers at high concentration showed not only low dark toxicity but also low toxicity under visible light. Such a behavior differs from that of other aggregation-induced emission antibacterial agents.55 Moreover, the as-synthesized polymers could cause highly efficient irreversible destruction of various pathogenic bacteria under UV irradiation. These characteristics will benefit the application of controllable in vitro sterilization in ordinary circumstances. Hence, for proof of concept, two practical sterilization models were designed by using P1a/2a as an antibacterial coating or spray (Figure 5e). In model I, the polymer film was first coated on the glass and S. aureus was then transplanted on the film. After 365 nm UV irradiation for 30 min, the bacteria were 100% killed under wet conditions where bacteria could germinate (Figures 5f and S40). In model II, the polymer suspension was sprayed on the glass slide covered with bacteria followed by 365 nm UV irradiation for 30 min. After plate cultivation, the bacteria were also found to be 100% killed (Figure 5f). These two models demonstrated that the polysulfonates are promising and flexible antibacterial materials for different situations, such as the surface sterilization of commodities, resistance to corrosion caused by microorganisms on ships, and customized bacterial scaffolds.

Postfunctionalization

Postfunctionalization is a powerful tool to endow polymers with more sophisticated structures and tunable functionalities.56−58 The vinyl bromine or vinyl iodine functionality of the halogen-rich polysulfonates enables them to undergo various postfunctionalization via efficient named organic reactions such as Suzuki coupling. To demonstrate such a possibility, we conducted the reaction of P1c/2a with boronic acid derivative 3a in the presence of Pd(PPh3)4 and K2CO3 to generate P1c/2a/3a with an Mw of 10 400 in a high yield of 79% and high conversion ratio of 88% (Scheme 1). This suggested that P1c/2a could serve as a versatile platform for postfunctionalization to further enrich the variety and functionalities of the polysulfonates. After modification, the absorption maximum shifted from 340 to 350 nm (Figure S41) while the emission maximum moved from 515 to 550 nm (Figure S42) due to the extension of the conjugation. P1c/2a/3a could also undergo photodegradation (Figures S43 and S44), but the degradation rate of P1c/2a/3a was much slower compared with that of the pristine polymer P1c/2a, which is probably due to the large steric hindrance and less electron deficiency of the hexylbenzene group compared with the iodine atom.

Scheme 1. Postfunctionalization to Polymer P1c/2a/3a.

Scheme 1

Open in a new tab

Conclusion

In summary, we developed a catalyst-free spontaneous polymerization for the facile synthesis of photoresponsive halogen-rich polysulfonates in 100% atom economy. The polymerization proceeded efficiently at room temperature in air within a short reaction time, generating a series of main-chain polysulfonates in excellent yields (up to 94%) and high molecular weights (up to 27 600) with a wide monomer scope and excellent solubility. Compared with traditional synthetic strategies of photoresponsive polymers, this new strategy did not require photosensitive monomers or strict synthetic conditions. The embedded halogen atoms enable them to undergo various efficient postfunctionalization reactions such as Suzuki coupling to further enrich the family of polysulfonates and endow them with advanced functionalities. These polysulfonates showed extraordinarily high and tunable refractive indices because of the halogen atoms and the sulfonate ester group. Notably, these photoresponsive polysulfonates could undergo photodegradation with remarkable fluorescence change and photoacid generation. Such a property allows the fabrication of 3D or dual-emissive photopatterns with only a single optical material. As strong photoacid generators, the polysulfonates could not only realize the UV-triggered, irreversible and broad-spectrum bacteria killing but also show hypotoxicity in high dosage or under natural light. P1a/2a was also demonstrated to be a highly efficient bactericide as an antibacterial layer or spray in two practical models. The catalyst-free spontaneous polymerization will provide new strategies for the facile synthesis of polysulfonates to greatly enrich the family of polyesters and photresponsive materials. The profound investigation on the properties and the various applications of polysulfonates will also provide more prospects for their practical usages, such as for adjusting intracellular pH, controllable sterilization, biopattern fabrication, tissue engineering, surface modification, and photocatalysts.

Experimental Procedures

Polymer Synthesis

Standard Schlenk technique was applied in all the polymerization reactions, and the synthetic procedure of P1a/2a (Table 1, entry 4) is given as an example. To a 15 mL Schlenk tube were added 4,4′-biphenyldisulfonic acid 2a (0.1 mmol), dihaloalkyne 1a (0.1 mmol), and 0.5 mL of HFIP/DCM (v/v, 1:8). The solution turned dark immediately after the addition of HFIP. The resulting solution was stirred at room temperature for 2 h. Upon completion, the unreacted sulfonic acid monomer was washed by adding 30 mL of water, followed by extraction with DCM three times. Subsequently, the organic layer was collected and concentrated, the solution was added dropwise into 100 mL of hexane, and the precipitate was finally collected after filtration, washed with hexane, and dried under vacuum at room temperature to a constant weight.

Acknowledgments

This work was financially supported by the National Natural Science Foundation of China (21788102 and 21705087), the Research Grants Council of Hong Kong (16304819, 16305618, and C6009-17G), the Innovation and Technology Commission (ITC-CNERC14SC01), the National Key Research and Development program of China (2018YFE0190200), the Science and Technology Plan of Shenzhen (JCYJ20170818113602462, JCYJ20180306174910791, JCYJ20170818113530705, and JCYJ20180306180231853), and A Project of Shandong Province Higher Educational Science and Technology Program (J18KA067). X.L. thanks Prof. Zhiyang Liu from Southeast University, Prof. Hanchu Huang from Sun Yat-sen University, and Dr. Xueqian Zhao, Dr. Xingguang Li, Dr. Zhongyan Hu, Mr. Eric Yan Hung Yu, and Miss Kristy Wing Ki Lam from HKUST for kind discussions and valuable help. X.L. also thanks Biosciences Central Research Facility of HKUST for technical assistance.

Supporting Information Available

The Supporting Information is available free of charge at https://pubs.acs.org/doi/10.1021/jacsau.0c00100.

  • Details of the materials, methods, synthetic procedures, and characterization data (IR, NMR, HRMS, etc.); photophysical properties and light refraction data of the polymers; photo of agar plates (PDF)

Author Contributions

○ X.L., X.L., and Y.H. contributed equally to this work.

The authors declare no competing financial interest.

Supplementary Material

au0c00100_si_001.pdf (2.4MB, pdf)

References

  1. Iamsaard S.; Villemin E.; Lancia F.; Aβhoff S.-J.; Fletcher S. P.; Katsonis N. Preparation of Biomimetic Photoresponsive Polymer Springs. Nat. Protoc. 2016, 11 (10), 1788–1797. 10.1038/nprot.2016.087. [DOI] [PubMed] [Google Scholar]
  2. Gelebart A. H.; Jan Mulder D.; Varga M.; Konya A.; Vantomme G.; Meijer E. W.; Selinger R. L. B.; Broer D. J. Making Waves in a Photoactive Polymer Film. Nature 2017, 546 (7660), 632–636. 10.1038/nature22987. [DOI] [PMC free article] [PubMed] [Google Scholar]
  3. De Poli M.; Zawodny W.; Quinonero O.; Lorch M.; Webb S. J.; Clayden J. Conformational Photoswitching of a Synthetic Peptide Foldamer Bound within a Phospholipid Bilayer. Science 2016, 352 (6285), 575–580. 10.1126/science.aad8352. [DOI] [PubMed] [Google Scholar]
  4. Luo W.; Wang G. Photo-Responsive Fluorescent Materials with Aggregation-Induced Emission Characteristics. Adv. Opt. Mater. 2020, 8, 2001362. 10.1002/adom.202001362. [DOI] [Google Scholar]
  5. Reed G. T.; Mashanovich G.; Gardes F. Y.; Thomson D. J. Erratum: Silicon Optical Modulators. Nat. Photonics 2010, 4 (9), 660–660. 10.1038/nphoton.2010.219. [DOI] [Google Scholar]
  6. Mogaki R.; Okuro K.; Aida T. Adhesive Photoswitch: Selective Photochemical Modulation of Enzymes under Physiological Conditions. J. Am. Chem. Soc. 2017, 139 (29), 10072–10078. 10.1021/jacs.7b05151. [DOI] [PubMed] [Google Scholar]
  7. Nocentini S.; Martella D.; Parmeggiani C.; Wiersma D. S. 3d Printed Photoresponsive Materials for Photonics. Adv. Opt. Mater. 2019, 7 (16), 1900156. 10.1002/adom.201900156. [DOI] [Google Scholar]
  8. Yang J.; Song J.-I.; Song Q.; Rho J. Y.; Mansfield E. D. H.; Hall S. C. L.; Sambrook M.; Huang F.; Perrier S. Hierarchical Self-Assembled Photo-Responsive Tubisomes from a Cyclic Peptide-Bridged Amphiphilic Block Copolymer. Angew. Chem., Int. Ed. 2020, 59 (23), 8860–8863. 10.1002/anie.201916111. [DOI] [PubMed] [Google Scholar]
  9. Wang H.; Zhu C. N.; Zeng H.; Ji X.; Xie T.; Yan X.; Wu Z. L.; Huang F. Reversible Ion-Conducting Switch in a Novel Single-Ion Supramolecular Hydrogel Enabled by Photoresponsive Host–Guest Molecular Recognition. Adv. Mater. 2019, 31 (12), 1807328. 10.1002/adma.201807328. [DOI] [PubMed] [Google Scholar]
  10. Kuznetsova N. A.; Malkov G. V.; Gribov B. G. Photoacid Generators. Application and Current State of Development. Russ. Chem. Rev. 2020, 89 (2), 173–190. 10.1070/RCR4899. [DOI] [Google Scholar]
  11. Kohse S.; Neubauer A.; Pazidis A.; Lochbrunner S.; Kragl U. Photoswitching of Enzyme Activity by Laser-Induced Ph-Jump. J. Am. Chem. Soc. 2013, 135 (25), 9407–9411. 10.1021/ja400700x. [DOI] [PubMed] [Google Scholar]
  12. Zhao G.; Wang T. Stereoselective Synthesis of 2-Deoxyglycosides from Glycals by Visible-Light-Induced Photoacid Catalysis. Angew. Chem., Int. Ed. 2018, 57 (21), 6120–6124. 10.1002/anie.201800909. [DOI] [PubMed] [Google Scholar]
  13. Zivic N.; Kuroishi P. K.; Dumur F.; Gigmes D.; Dove A. P.; Sardon H. Recent Advances and Challenges in the Design of Organic Photoacid and Photobase Generators for Polymerizations. Angew. Chem., Int. Ed. 2019, 58 (31), 10410–10422. 10.1002/anie.201810118. [DOI] [PubMed] [Google Scholar]
  14. Bertrand O.; Gohy J.-F. Photo-Responsive Polymers: Synthesis and Applications. Polym. Chem. 2017, 8 (1), 52–73. 10.1039/C6PY01082B. [DOI] [Google Scholar]
  15. Li L.; Scheiger J. M.; Levkin P. A. Design and Applications of Photoresponsive Hydrogels. Adv. Mater. 2019, 31 (26), 1807333. 10.1002/adma.201807333. [DOI] [PMC free article] [PubMed] [Google Scholar]
  16. Ariyasu S.; Hanaya K.; Tsunoda M.; Kitamura M.; Hayase M.; Abe R.; Aoki S. Photochemical Cleavage Reaction of 8-Quinolinyl Sulfonates That Are Halogenated and Nitrated at the 7-Position. Chem. Pharm. Bull. 2011, 59 (11), 1355–1362. 10.1248/cpb.59.1355. [DOI] [PubMed] [Google Scholar]
  17. Xu W.; Li T.; Li G.; Wu Y.; Miyashita T. Novel Polymeric Nonionic Photoacid Generators and Corresponding Polymer Langmuir–Blodgett (Lb) Films for Photopatterning. J. Photochem. Photobiol., A 2011, 219 (1), 50–57. 10.1016/j.jphotochem.2011.01.015. [DOI] [Google Scholar]
  18. Kageyama Y.; Ohshima R.; Sakurama K.; Fujiwara Y.; Tanimoto Y.; Yamada Y.; Aoki S. Photochemical Cleavage Reactions of 8-Quinolinyl Sulfonates in Aqueous Solution. Chem. Pharm. Bull. 2009, 57 (11), 1257–1266. 10.1248/cpb.57.1257. [DOI] [PubMed] [Google Scholar]
  19. Seidler K.; Griesser M.; Kury M.; Harikrishna R.; Dorfinger P.; Koch T.; Svirkova A.; Marchetti-Deschmann M.; Stampfl J.; Moszner N.; Gorsche C.; Liska R. Vinyl Sulfonate Esters: Efficient Chain Transfer Agents for the 3d Printing of Tough Photopolymers without Retardation. Angew. Chem., Int. Ed. 2018, 57 (29), 9165–9169. 10.1002/anie.201803747. [DOI] [PubMed] [Google Scholar]
  20. Thomson D. W.; Ehlers G. F. L. Aromatic Polysulfonates: Preparation and Properties. J. Polym. Sci., Part A: Gen. Pap. 1964, 2 (3), 1051–1056. 10.1002/pol.1964.100020303. [DOI] [Google Scholar]
  21. Campbell R. W.; Hill H. W. Polymerization of 4-Hydroxybenzenesulfonyl Chloride. Macromolecules 1973, 6 (4), 492–495. 10.1021/ma60034a003. [DOI] [Google Scholar]
  22. Wang H.; Zhou F.; Ren G.; Zheng Q.; Chen H.; Gao B.; Klivansky L.; Liu Y.; Wu B.; Xu Q.; Lu J.; Sharpless K. B.; Wu P. Sufex-Based Polysulfonate Formation from Ethenesulfonyl Fluoride–Amine Adducts. Angew. Chem., Int. Ed. 2017, 56 (37), 11203–11208. 10.1002/anie.201701160. [DOI] [PMC free article] [PubMed] [Google Scholar]
  23. Gao B.; Zhang L.; Zheng Q.; Zhou F.; Klivansky L. M.; Lu J.; Liu Y.; Dong J.; Wu P.; Sharpless K. B. Bifluoride-Catalysed Sulfur(Vi) Fluoride Exchange Reaction for the Synthesis of Polysulfates and Polysulfonates. Nat. Chem. 2017, 9 (11), 1083–1088. 10.1038/nchem.2796. [DOI] [PMC free article] [PubMed] [Google Scholar]
  24. Xu L.; Wu P.; Dong J.. New Polymers from Sufex Click Chemistry: Syntheses and Perspectives. In Synthetic Polymer Chemistry: Innovations and Outlook; The Royal Society of Chemistry: 2019; Chapter 1, pp 1–31. [Google Scholar]
  25. Yang C.; Flynn J. P.; Niu J. Facile Synthesis of Sequence-Regulated Synthetic Polymers Using Orthogonal Sufex and Cuaac Click Reactions. Angew. Chem., Int. Ed. 2018, 57 (49), 16194–16199. 10.1002/anie.201811051. [DOI] [PubMed] [Google Scholar]
  26. Zeng X.; Liu S.; Shi Z.; Xu B. Hydrogen Bonding Cluster-Enabled Addition of Sulfonic Acids to Haloalkynes: Access to Both (E)- and (Z)-Alkenyl Sulfonates. Org. Lett. 2016, 18 (19), 4770–4773. 10.1021/acs.orglett.6b02061. [DOI] [PubMed] [Google Scholar]
  27. Pigulski B.; Arendt A.; Tomilin D. N.; Sobenina L. N.; Trofimov B. A.; Szafert S. Transition-Metal Free Mechanochemical Approach to Polyyne Substituted Pyrroles. J. Org. Chem. 2016, 81 (19), 9188–9198. 10.1021/acs.joc.6b01732. [DOI] [PubMed] [Google Scholar]
  28. Zhang J.; Sun J. Z.; Qin A.; Tang B. Z. Transition-Metal-Free Polymerization of Bromoalkynes and Phenols. Macromolecules 2019, 52 (8), 2949–2955. 10.1021/acs.macromol.9b00306. [DOI] [Google Scholar]
  29. Katoono R.; Tanaka Y.; Kusaka K.; Fujiwara K.; Suzuki T. Dynamic Figure Eight Chirality: Multifarious Inversions of a Helical Preference Induced by Complexation. J. Org. Chem. 2015, 80 (15), 7613–7625. 10.1021/acs.joc.5b01206. [DOI] [PubMed] [Google Scholar]
  30. Bowles D. M.; Anthony J. E. A Reiterative Approach to 2,3-Disubstituted Naphthalenes and Anthracenes. Org. Lett. 2000, 2 (1), 85–87. 10.1021/ol991254w. [DOI] [PubMed] [Google Scholar]
  31. Colomer I.; Chamberlain A. E. R.; Haughey M. B.; Donohoe T. J. Hexafluoroisopropanol as a Highly Versatile Solvent. Nat. Rev. Chem. 2017, 1 (11), 0088. 10.1038/s41570-017-0088. [DOI] [Google Scholar]
  32. Andraos J.; Barclay G. G.; Medeiros D. R.; Baldovi M. V.; Scaiano J. C.; Sinta R. Model Studies on the Photochemistry of Phenolic Sulfonate Photoacid Generators. Chem. Mater. 1998, 10 (6), 1694–1699. 10.1021/cm980052b. [DOI] [Google Scholar]
  33. Yang J.-C.; Ho Y.-C.; Chan Y.-H. Ultrabright Fluorescent Polymer Dots with Thermochromic Characteristics for Full-Color Security Marking. ACS Appl. Mater. Interfaces 2019, 11 (32), 29341–29349. 10.1021/acsami.9b10393. [DOI] [PubMed] [Google Scholar]
  34. Gao Q.; Xiong L.-H.; Han T.; Qiu Z.; He X.; Sung H. H. Y.; Kwok R. T. K.; Williams I. D.; Lam J. W. Y.; Tang B. Z. Three-Component Regio- and Stereoselective Polymerizations toward Functional Chalcogen-Rich Polymers with AIE-Activities. J. Am. Chem. Soc. 2019, 141 (37), 14712–14719. 10.1021/jacs.9b06493. [DOI] [PubMed] [Google Scholar]
  35. Han T.; Deng H.; Qiu Z.; Zhao Z.; Zhang H.; Zou H.; Leung N. L. C.; Shan G.; Elsegood M. R. J.; Lam J. W. Y.; Tang B. Z. Facile Multicomponent Polymerizations toward Unconventional Luminescent Polymers with Readily Openable Small Heterocycles. J. Am. Chem. Soc. 2018, 140 (16), 5588–5598. 10.1021/jacs.8b01991. [DOI] [PubMed] [Google Scholar]
  36. Wang Y.; Tang Z.; Correa-Duarte M. A.; Liz-Marzán L. M.; Kotov N. A. Multicolor Luminescence Patterning by Photoactivation of Semiconductor Nanoparticle Films. J. Am. Chem. Soc. 2003, 125 (10), 2830–2831. 10.1021/ja029231r. [DOI] [PubMed] [Google Scholar]
  37. Devatha G.; Rao A.; Roy S.; Pillai P. P. Förster Resonance Energy Transfer Regulated Multicolor Photopatterning from Single Quantum Dot Nanohybrid Films. ACS Energy Lett. 2019, 4 (7), 1710–1716. 10.1021/acsenergylett.9b00832. [DOI] [Google Scholar]
  38. Malak S. T.; Jung J.; Yoon Y. J.; Smith M. J.; Lin C. H.; Lin Z.; Tsukruk V. V. Large-Area Multicolor Emissive Patterns of Quantum Dot–Polymer Films Via Targeted Recovery of Emission Signature. Adv. Opt. Mater. 2016, 4 (4), 608–619. 10.1002/adom.201500670. [DOI] [Google Scholar]
  39. Shen H.; Wu Y.; Fang L.; Ye S.; Wang Z.; Liu W.; Cheng Z.; Zhang J.; Wang Z.; Yang B. From 1d to 3d: A New Route to Fabricate Tridimensional Structures Via Photo-Generation of Silver Networks. RSC Adv. 2015, 5 (36), 28633–28642. 10.1039/C4RA17258B. [DOI] [Google Scholar]
  40. Wu Y.; Zhang K.; Yang B. Ordered Hybrid Micro/Nanostructures and Their Optical Applications. Adv. Opt. Mater. 2019, 7 (7), 1800980. 10.1002/adom.201800980. [DOI] [Google Scholar]
  41. Li Y.; Zhang J.; Liu W.; Li D.; Fang L.; Sun H.; Yang B. Hierarchical Polymer Brush Nanoarrays: A Versatile Way to Prepare Multiscale Patterns of Proteins. ACS Appl. Mater. Interfaces 2013, 5 (6), 2126–2132. 10.1021/am3031757. [DOI] [PubMed] [Google Scholar]
  42. Wu P.; Wang J.; Jiang L. Bio-Inspired Photonic Crystal Patterns. Mater. Horiz. 2020, 7 (2), 338–365. 10.1039/C9MH01389J. [DOI] [Google Scholar]
  43. Mark J. E.Physical Properties of Polymers Handbook; Springer: 2007; Vol. 1076. [Google Scholar]
  44. Han T.; Yao Z.; Qiu Z.; Zhao Z.; Wu K.; Wang J.; Poon A. W.; Lam J. W. Y.; Tang B. Z. Photoresponsive Spiro-Polymers Generated in Situ by C–H-Activated Polyspiroannulation. Nat. Commun. 2019, 10 (1), 5483. 10.1038/s41467-019-13308-w. [DOI] [PMC free article] [PubMed] [Google Scholar]
  45. Iasilli G.; Francischello R.; Lova P.; Silvano S.; Surace A.; Pesce G.; Alloisio M.; Patrini M.; Shimizu M.; Comoretto D.; Pucci A. Luminescent Solar Concentrators: Boosted Optical Efficiency by Polymer Dielectric Mirrors. Mater. Chem. Front. 2019, 3 (3), 429–436. 10.1039/C8QM00595H. [DOI] [Google Scholar]
  46. Geervliet T. A.; Gavrila I.; Iasilli G.; Picchioni F.; Pucci A. Luminescent Solar Concentrators Based on Renewable Polyester Matrices. Chem. - Asian J. 2019, 14 (6), 877–883. 10.1002/asia.201801690. [DOI] [PubMed] [Google Scholar]
  47. Battisti A.; Ambrosetti M.; Ruggeri G.; Cappelli C.; Pucci A. A 4,4′-Bis(2-Benzoxazolyl)Stilbene Luminescent Probe: Assessment of Aggregate Formation through Photophysics Experiments and Quantum-Chemical Calculations. Phys. Chem. Chem. Phys. 2018, 20 (41), 26249–26258. 10.1039/C8CP04450C. [DOI] [PubMed] [Google Scholar]
  48. Borelli M.; Iasilli G.; Minei P.; Pucci A. Fluorescent Polystyrene Films for the Detection of Volatile Organic Compounds Using the Twisted Intramolecular Charge Transfer Mechanism. Molecules 2017, 22 (8), 1306. 10.3390/molecules22081306. [DOI] [PMC free article] [PubMed] [Google Scholar]
  49. Liu L.; Wang X.; Zhu S.; Yao C.; Ban D.; Liu R.; Li L.; Wang S. Controllable Targeted Accumulation of Fluorescent Conjugated Polymers on Bacteria Mediated by a Saccharide Bridge. Chem. Mater. 2020, 32 (1), 438–447. 10.1021/acs.chemmater.9b04034. [DOI] [Google Scholar]
  50. Zhu C.; Liu L.; Yang Q.; Lv F.; Wang S. Water-Soluble Conjugated Polymers for Imaging, Diagnosis, and Therapy. Chem. Rev. 2012, 112 (8), 4687–4735. 10.1021/cr200263w. [DOI] [PubMed] [Google Scholar]
  51. Zhu C.; Yang Q.; Lv F.; Liu L.; Wang S. Conjugated Polymer-Coated Bacteria for Multimodal Intracellular and Extracellular Anticancer Activity. Adv. Mater. 2013, 25 (8), 1203–1208. 10.1002/adma.201204550. [DOI] [PubMed] [Google Scholar]
  52. Li X.; Bai H.; Yang Y.; Yoon J.; Wang S.; Zhang X. Supramolecular Antibacterial Materials for Combatting Antibiotic Resistance. Adv. Mater. 2018, 31 (5), 1805092. 10.1002/adma.201805092. [DOI] [PubMed] [Google Scholar]
  53. Li P.; Poon Y. F.; Li W.; Zhu H.-Y.; Yeap S. H.; Cao Y.; Qi X.; Zhou C.; Lamrani M.; Beuerman R. W.; Kang E.-T.; Mu Y.; Li C. M.; Chang M. W.; Jan Leong S. S.; Chan-Park M. B. A Polycationic Antimicrobial and Biocompatible Hydrogel with Microbe Membrane Suctioning ability. Nat. Mater. 2011, 10 (2), 149–156. 10.1038/nmat2915. [DOI] [PubMed] [Google Scholar]
  54. Luo Y.; Wang C.; Peng P.; Hossain M.; Jiang T.; Fu W.; Liao Y.; Su M. Visible Light Mediated Killing of Multidrug-Resistant Bacteria Using Photoacids. J. Mater. Chem. B 2013, 1 (7), 997–1001. 10.1039/C2TB00317A. [DOI] [PubMed] [Google Scholar]
  55. Liu X.; Li M.; Han T.; Cao B.; Qiu Z.; Li Y.; Li Q.; Hu Y.; Liu Z.; Lam J. W. Y.; Hu X.; Tang B. Z. In Situ Generation of Azonia-Containing Polyelectrolytes for Luminescent Photopatterning and Superbug Killing. J. Am. Chem. Soc. 2019, 141 (28), 11259–11268. 10.1021/jacs.9b04757. [DOI] [PubMed] [Google Scholar]
  56. Niu J.; Lunn D. J.; Pusuluri A.; Yoo J. I.; O’Malley M. A.; Mitragotri S.; Soh H. T.; Hawker C. J. Engineering Live Cell Surfaces with Functional Polymers Via Cytocompatible Controlled Radical Polymerization. Nat. Chem. 2017, 9 (6), 537–545. 10.1038/nchem.2713. [DOI] [PubMed] [Google Scholar]
  57. Liu Y.; Mao L.; Liu X.; Liu M.; Xu D.; Jiang R.; Deng F.; Li Y.; Zhang X.; Wei Y. A Facile Strategy for Fabrication of Aggregation-Induced Emission (AIE) Active Fluorescent Polymeric Nanoparticles (FPNs) Via Post Modification of Synthetic Polymers and Their Cell Imaging. Mater. Sci. Eng., C 2017, 79, 590–595. 10.1016/j.msec.2017.05.108. [DOI] [PubMed] [Google Scholar]
  58. Wang S.; Fu C.; Wei Y.; Tao L. Facile One-Pot Synthesis of New Functional Polymers through Multicomponent Systems. Macromol. Chem. Phys. 2014, 215 (6), 486–492. 10.1002/macp.201300738. [DOI] [Google Scholar]

Associated Data

This section collects any data citations, data availability statements, or supplementary materials included in this article.

Supplementary Materials

au0c00100_si_001.pdf (2.4MB, pdf)

Articles from JACS Au are provided here courtesy of American Chemical Society

RESOURCES