Evaporative assembly of ordered microporous films and their hierarchical structures from amphiphilic random copolymers

Abstract

Ordered microporous films were obtained via evaporative assembly from amphiphilic random copolymers of poly(acryloyl chloride) with self-crosslinked components. The quality and morphology of the porous structures were found to be highly dependent on the ratio of good solvent for the polymer (e.g. acetone) and nonsolvent (e.g. toluene), choice of nonsolvent, and surface chemistry of the supporting substrate. When increasing the polymer concentration in acetone-toluene solution, a morphological evolution from vesicles to microporous films with decreased pore size was observed. Using SU-8 micropillar arrays with spatially controlled surface chemistry to direct the evaporative assembly, we constructed hierarchical microporous structures with tunable pore size and symmetry (e.g. square arrays vs. hexagonal arrays). Finally, we selectively assembled TOPO-stabilized CdSe nanocrystals into the hydrophobic core of the random copolymers dispersed in acetone-toluene, and created fluorescent microporous structures after solvent evaporation.

Breath Figures: Fabrication of Honeycomb Porous Films Induced by Marangoni Instabilities

“…The polymer concentration also plays an important role on the control of pore size. As reported by several studies, for a given polymer/solvent system, the increase of the concentration of polymer solution systematically led to lower pore diameter [93,97,98,[101][102][103][104][105][106][107][108]. For higher polymer concentration, the precipitation of the thin polymer layer at the interface of polymer solution and water droplet occurs in earlier stage, hence limiting droplet growth.…”

Single Solvent‐Based Film Casting Method for the Production of Porous Polymer Films

“…Using a mixture of immiscible solvents has also been explored to form porous films where one solvent with comparatively slower evaporation rate is used to form droplets which subsequently form the pores within the film during the drying process. [28] Porous Film A single solvent-based film casting process for fabricating porous polymer films is developed in this study. The porous film is produced by mixing concentrated polylactic acid (PLA)/chloroform solution (20 wt%) and fresh chloroform solvent is followed by film casting.…”

“…The porogen removal process may cause adverse effects to the host material. Using a mixture of immiscible solvents has also been explored to form porous films where one solvent with comparatively slower evaporation rate is used to form droplets which subsequently form the pores within the film during the drying process …”

Synthesis and self-assembly of partially sulfonated poly(arylene ether sulfone)s and their role in the formation of Cu2S nanowires

“…Amphiphilic random copolymers consisting of randomly distributed hydrophilic and hydrophobic repeating units in the polymer backbone are another class of amphiphilic polymers but much rarer than amphiphilic block polymers. [9][10][11][12][13][14][15][16][17][18][19][20][21][22] However, amphiphilic random copolymer has distinct synthetic advantages over amphiphilic block polymers because they can be synthesized by one-step copolymerization of hydrophilic and hydrophobic monomers avoiding multi-step processes. Similar to amphiphilic block copolymers, formation of spherical micelles, multi-micellar aggregates, and vesicles of amphiphilic random copolymers in aqueous media has been observed and their encapsulation capability of hydrophobic guests has been investigated.…”