Polymer films with a self‐organized honeycomb morphology

Abstract

Porous polymer films with a regular arrangement of pores (see figure) with a narrow pore size distribution have recently been reported. The preparation of the films from a variety of star polystyrenes, micellar polystyrenes, and block copolymers, the mechanism of formation, and the potential applications of the materials are presented .

Microsphere Pattern Prepared by a “Reverse” Breath Figure Method

“…12 Among the many methods, [13][14][15][16] the water-droplet templating method, namely the breath figure method, is mostly used for the preparation periodic array porous films. 1,[17][18][19][20][21][22][23] During the preparation, a polymer solution is cast on a substrate under a humid atmosphere. The cooling surface caused by rapid solvent evaporation results in the water vapor condensation, and then the condensed water droplets are trapped into the solution.…”

Porous Thin Films Based on Photo-Cross-Linked Star-Shaped Poly(d,l-lactide)s

“…In another study, 8 honeycomb structures were prepared using six-arm star polystyrene (PS), and a strong correlation between the number of arms, arm length, end-group functionality, and pore diameter were demonstrated. Other polymers that were used for the fabrication of honeycomb structures have included random and block copolymers of polystyrene (PS), [9][10][11][12][13][14][15][16]23 poly-(2-vinyl pyridine) (P2VP), 17 poly(p-phenyleneethynylene) (PPE), 18,19 fluorinated PMMA copolymers, 20 and an amphiphilic copolymer containing dendronized poly(alkyl methacrylate) and linear poly(ethylene oxide) blocks. 21 The exploitation of a wide range of polymers for the successful fabrication of microporous structures using the breath figure methodology continues to generate considerable interest, and recent efforts are now focused on developing such patterned porosity on biocompatible polymers.…”

“…2 Although many lithographic techniques [3][4][5][6] are known for the successful fabrication of porous thin films, the breath figure approach has received considerable interest due to the simple, inexpensive, and robust mechanism of pattern formation. [7][8][9][10][11][12][13][14][15][16][17][18][19][20][21] Breath figures are derived from ordered micrometer-sized water droplets that form during vapor condensation onto a polymer solution surface. 22 The process, also known as the solvent evaporation method, occurs as an appropriate solvent evaporates under humid conditions, leading to a temperature decrease at the air-liquid interface and subsequent water condensation.…”

Functional Porous Structures Based on the Pyrolysis of Cured Templates of Block Copolymer and Phenolic Resin

“…[2,[11][12][13][14][15][16][17][18][19][20] These materials can have large void volumes and high internal surface areas, but the supramolecular materials often tend to collapse upon emptying the pores. Several approaches have also been presented to prepare mesoporous and macroporous materials, such as "track-etching", [4][5][6] using honeycomb structures, [27][28][29] and emptying nanostructured templates (e.g., sol-gel processing of surfactants or block copolymers, [7][8][9][10] selective degradation of material with UV exposure, [24][25][26] pyrolysis, [21][22][23]34] and selective removal of lowmolecular-weight amphiphiles (combs) from hierarchically self-assembled polymeric comb-coil supramolecules [35,36] ). Block copolymers provide ideal structures for templates, as, by a facile route, they self-assemble into various structures as a result of the repulsion between the covalently bonded blocks; examples include the spherical, cylindrical, lamellar, and gyroid structures.…”