Breath Figures as a Dynamic Templating Method for Polymers and Nanomaterials

Abstract

This review describes the use of breath figures as a templating method for the fabrication of self‐assembled polymeric‐ and nanoparticle‐based micro‐ and nanostructures. If moist air is blown over a solution of a polymer or stabilized nanoparticles in an organic solvent, such as carbon disulfide, benzene, or chloroform, evaporative cooling leads to the formation of water droplets on the liquid surface. The monodisperse droplets arrange into a hexagonal array and sink into the polymer solution. Removal of the solvent and the water leaves an imprint of the water droplets as a hollow, air‐filled, hexagonally ordered, polymeric bubble array. Progress in the field of breath‐figure formation is reviewed. The application of breath figures for the generation of functional structures in chemistry and materials science is discussed.

Microsphere Pattern Prepared by a “Reverse” Breath Figure Method

“…Upon casting a drop of the polymer solution onto a glass slide in a static MeOH vapor atmosphere, the solution surface turned turbid like the usual breath figure process. 1,21 This observation can be easily understood by the rapid evaporation of the volatile solvent resulting in the cooling of the solution surface and the condensation of MeOH vapor into tiny droplets, which disperses in the polymer solution thereafter. After the complete evaporation of the solvent, microsphere patterns ( Figure 1) were observed on the glass substrate, which were totally different from the porous honeycomb structure of the films prepared in the atmosphere of pure water vapor (breath figure process).…”

“…24,25 However, literature search indicates that all the honeycomb porous polymeric films have been fabricated under water vapor. 1,26 This might make people wonder: what would the structure of the materials be if a polymer solution was cast in an organic nonsolvent vapor atmosphere? Therefore, linear and star-shaped poly(styrene-block-butadiene) copolymers dissolved in solvents such as toluene, trichloroform, and dichloromethane were cast onto the surface of glass substrate in methanol or ethanol vapor atmosphere.…”

“…The self-assembly of polymer is of critical importance for the fabrication of nanostructured and microstructured devices such as membranes, films, spheres, and monoliths, [1][2][3][4][5] which have great potential application in the fields of separation, 6 tissue engineering, 7 drug delivery, 8 photonic band gap, 9 electronic, 10 catalysis, 11 and lithography. 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.…”

“…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.…”

Square Packing and Structural Arrangement of ABC Triblock Copolymer Spheres in Thin Films

“…The other possible mechanism could be analogous to the widely observed breath figure (BF) formation on drop-cast polymer films. [62][63][64][65][66][67][68][69][70][71][72] In earlier publications, 41,42 we proposed the possibility that water condensation onto the PEO-based block copolymers leads to PEO domain ordering. After solvent annealing, the solvent evaporation causes the cooling of the film surface.…”