Table 1.

Summary of various fabrication approaches for the formation of nanoporous polymeric materials.

Approach	Polymer Used	Pore Diameter (nm)	Pore Density (cm−2)	Film Thickness	Film Uniformity	Ref.
Lithography
Optical Lithography	various photoresists	~100	–	–	High	24
Electron Beam Lithography	PMMA	10	–	–	High	31, 32
Aperture Array Lithography	PMMA	200–350 A	2.4×107–4×108	160 nm	High	33
Colloidal Lithography	PES	230	109	0.5 μm	High	34
	PIP	55	5×109	40 nm	High	35
Pattern Transfer
Nanowire Templated	PCL	20–30	5×109	0.5 μm	High	41
Molding/Imprint	PMMA	25	7×109	100 nm	High	42
	PS	25–30	5×1010	–	High	116
Track Etch	PC, PE	15	<109	5–20 μm	High	46, 47
Solvent-based Techniques
Immersion Precipitation	PVDF, PSF	20–120	–	200 μm	Moderate	52
Phase Separation	PCL	5–200	2×108	50 μm	Low	53
CO2 Foaming	PIM, PSF	20–50	~1010	–	Moderate-High	54
	PPQ	8–24	–	2–50 μm	Moderate	55
Light Induced Polymerization	complex monomer mixture	20–40	–	–	–	58
Block Copolymer
	PS-co-PMMA	15	~5×1010 B	80 nm C	Moderate-High	77
	PS-co-PL	16	~1011	300 μm	High D(h)	78
	PS-co-PIP	20–30	~2×1010	100–300 μm	High	76
Reactive Pore Formation	PS-co-PMMA	3–8	1011	30–300 nm	High	80, 81
Substrate Aligned Pores	PS-co-PMMA	~25	~1011	<0.1 μm	High	86
Electric Field Aligned Pores	PS-co-PMMA	14–50	1010–1011	~1 μm	Moderate-High	85
Triblock Copolymer	PL-co-PDMA-co-PS	19	1011	–E	High	87
Graft Copolymer	PVDF-graft-POEM	~2	>1011	~3.5 μm F	Moderate-High	82
Asymmetric Membranes	PS-co-PDMAEMA	20–80	–	50 nm – 1 μm 85 μm total	Moderate	84
	PS-co-P4VP	40	2.4×1010	200–300 nm 100 μm total	High	83
Polyelectrolyte Multilayers
	PAA/PAH	50–200	–	50–80 nm	High	66
	PAA/PAH/P4VP	10–50	–	~25nm	Moderate	71
	PAA/PAH	30–40	~1010	0.2–0.7 μm	Moderate-High	67
Spin Assisted Deposition	PAH/PSS	~40	~5×1010	15–30 nm	Moderate-High	70
Nanoparticle Templated Pores	PAA/PAH/silica nanoparticles	20–30	~2×1010	<100 nm	Moderate	72
Spatially Patterned Films	PAArVBA/ PAH/PSS	~10	–	~150 nm	–	68
Asymmetric Membranes	PEI/PAA	~100	–	~10 μm	Low-Moderate	69
Biologically-Derived Materials
Cellulose-based	Cellulose esters	< 10 G	~1011	>100 μm	Moderate	89, 117
Cellular Layers (S-layers)	bacterium-based	4–5	>1011	10’s of nm H	High	92, 93, 104, 118
Peptide-based Multilayers	polypeptides	50–150	–	–	–	73
Engineered polypeptides	P(GPV)	~70	~5×109	8 nm I	Moderate-High	97

Abbreviated polymers are as follows: PC - poly(carbonate), PE - poly(ester), PS - poly(styrene), PMMA - poly(methyl methacrylate), PL – poly(lactide), PIP -poly(isoprene), PAA= poly(acrylic acid), PAH - poly(allylamine hydrochloride), PCL - poly(caprolactone), PSS - poly(sodium-4-styrene sulfonate), POEM -poly(oxyethylene methacrylate), PVDF - poly(vinylidene fluoride), PDMA - poly(N,N-dimethylacrylamide), PDMAEMA - poly(N,N-dimethylaminoethyl methacrylate), P4VP - poly(4-vinylpyridine), PAArVBA - poly(acrylic acid-ran-vinylbenzylacrylate), PEI - poly(ethylene imine), PES - poly(ether sulfone), PSF - polysulfone, PIM -Polyimide, P(GPV) - peptide polymer with gylcine, L-proline, and L-valine monomer base units, PPQ – poly(phenylquinoxaline)