Fig. 2. General chemical activity at microparticle–water interfaces across commodity plastics.
a, Confocal fluorescence images of microplastics with different polymer compositions incubated with 5 μM APF in PBS, with each corresponding chemical structure illustrated to the right. b, Quantification of APF fluorescence intensity measured at particle surfaces for different commodity plastics in PBS buffer. The background is subtracted from the fluorescence intensity of the same APF solution without adding microplastics. Values are presented as area-weighted mean fluorescence intensities ± s.d from particle regions for PP (n = 10), PE (n = 7), PS (n = 17), PVC (n = 10), PET (n = 6), and PMMA (n = 9), respectively. c, Correlation between the water contact angle (θ) reported from the Accu Dyne Test Surface Energy Database37 and APF fluorescence intensity measured at microplastic particle surfaces (same data from panel b) for different commodity plastics. Scale bars, 50 µm (a).