Annealing Process Dependence of the Self-Assembly of Rod–Coil Block Copolymer Thin Films

Self-Assembly of Block Copolymers in Thin Films Swollen-Rich in Solvent Vapors

In this study we have employed a polymer processing method based on solvent vapor annealing in order to condense relatively large amounts of solvent vapors onto thin films of block copolymers and thus to promote their self-assembly into ordered nanostructures. As revealed by the atomic force microscopy, a periodic lamellar morphology of poly(2-vinylpyridine)-b-polybutadiene and an ordered morphology comprised of hexagonally-packed structures made of poly(2-vinylpyridine)-b-poly(cyclohexyl methacrylate) were both successfully generated on solid substrates for the first time.

Well-Defined Nanostructures by Block Copolymers and Mass Transport Applications in Energy Conversion

With the speedy progress in the research of nanomaterials, self-assembly technology has captured the high-profile interest of researchers because of its simplicity and ease of spontaneous formation of a stable ordered aggregation system. The self-assembly of block copolymers can be precisely regulated at the nanoscale to overcome the physical limits of conventional processing techniques. This bottom-up assembly strategy is simple, easy to control, and associated with high density and high order, which is of great significance for mass transportation through membrane materials. In this review, to investigate the regulation of block copolymer self-assembly structures, we systematically explored the factors that affect the self-assembly nanostructure. After discussing the formation of nanostructures of diverse block copolymers, this review highlights block copolymer-based mass transport membranes, which play the role of “energy enhancers” in concentration cells, fuel cells, and rechargeable batteries. We firmly believe that the introduction of block copolymers can facilitate the novel energy conversion to an entirely new plateau, and the research can inform a new generation of block copolymers for more promotion and improvement in new energy applications.

Solvent-assisted self-assembly of block copolymer thin films

Solvent-assisted block copolymer self-assembly is a compelling method for processing and advancing practical applications of these materials due to the exceptional level of the control of BCP morphology and significant acceleration of ordering kinetics. Despite substantial experimental and theoretical efforts devoted to understanding of solvent-assisted BCP film ordering, the development of a universal BCP patterning protocol remains elusive; possibly due to a multitude of factors which dictate the self-assembly scenario. The aim of this review is to aggregate both seminal reports and the latest progress in solvent-assisted directed self-assembly and to provide the reader with theoretical background, including the outline of BCP ordering thermodynamics and kinetics phenomena. We also indicate significant BCP research areas and emerging high-tech applications where solvent-assisted processing might play a dominant role.

Selective sequential infiltration synthesis of ZnO in the liquid crystalline phase of silicon-containing rod-coil block copolymers

The combination of block copolymer (BCP) thin film self-assembly and selective infiltration synthesis of inorganic materials into one BCP block provides access to various organic-inorganic hybrids. Here, we apply sequential infiltration synthesis, a vapor-phase hybridization technique, to selectively introduce ZnO into the organic microdomains of silicon-containing rod-coil diblock copolymers and a triblock terpolymer, polydimethylsiloxane (PDMS)-b-poly{2,5-bis[(4-methoxyphenyl)-oxycarbonyl]styrene} (PDMS-b-PMPCS) and PDMS-b-polystyrene-b-PMPCS (PDMS-b-PS-b-PMPCS), in which the PMPCS rod block is a liquid crystalline polymer. The in-plane cylindrical PDMS-b-PMPCS and core-shell cylindrical and hexagonally perforated lamellar PDMS-b-PS-b-PMPCS films were infiltrated with ZnO with high selectivity to the PMPCS. The etching contrast between PDMS, PS and the ZnO-infused PMPCS enables the fabrication of ZnO/SiO_x binary composites by plasma etching and reveals the core-shell morphology of the triblock terpolymer.

Sub-5 nm homeotropically aligned columnar structures of hybrids constructed by porphyrin and oligo(dimethylsiloxane)

A series of tetraphenylporphyrin-based thermotropic liquid crystals containing oligo(dimethylsiloxane) were synthesized. These disc-coil hybrids form ordered nanostructures with periodic sizes on the sub-5 nm scale, including oblique columnar, lamellar, and hexagonal columnar phases. Films with sub-5 nm line patterns and homeotropically aligned columnar structures can be obtained by substrate-induced self-assembly.