Herein, this work aims to carry out controlled selfassembly of single-composition block copolymer for the fabrication of various nanonetwork silica monoliths. With the use of lamellaeforming polystyrene-block-polydimethylsiloxane (PS-b-PDMS), nanonetwork-structured films could be fabricated by solvent annealing using a PS-selective solvent (chloroform). By simply tuning the flow rate of nitrogen purge to the PS-selective solvent for the controlled self-assembly of the PS-b-PDMS, gyroid-and diamond-structured monoliths can be formed due to the difference in the effective volume of PS in the PS-b-PDMS during solvent annealing. As a result, well-ordered nanonetwork SiO 2 (silica) monoliths can be fabricated by templated sol−gel reaction using hydrofluoric acid etched PS-b-PDMS film as a template followed by the removal of the PS. This bottom-up approach for the fabrication of nanonetwork materials through templated synthesis is appealing to create nanonetwork materials for various applications.

Bioinspired from structural coloration of butterfly wing structure, this work aims to fabricate nanoporous chitosan for UVC reflection. By taking advantage of self-assembled polystyrene-b-polydimethylsiloxane (PS-b-PDMS) with double gyroid texture followed by hydrofluoric acid etching of PDMS block, nanoporous PS with well-defined nanochannels can be fabricated, and used as a template for templated crosslinking reaction of chitosan through a multiple pore-filling process. Well-ordered nanoporous chitosan with shifting networks in nanoscale can be successfully fabricated after removal of the PS template. With the low absorption of chitosan in the ultraviolet region and the shifting networks for opening the bandgap, it is appealing to exploit the nanonetwork chitosan as high reflective materials for UVC optical devices, as evidenced by finite-difference time-domain (FDTD) simulation and optical measurements experimentally.

Herein, this work aims to fabricate well-ordered nanonetwork epoxy resin modified with poly(butyl acrylate)-b-poly(methyl methacrylate) (PBA-b-PMMA) block copolymer (BCP) for enhanced energy dissipation using a self-assembled diblock copolymer of polystyrene-b-poly(dimethylsiloxane) (PS-b-PDMS) with gyroid and diamond structures as templates. A systematic study of mechanical properties using nanoindentation of epoxy resin with gyroid- and diamond-structures after modification revealed significant enhancement in energy dissipation, with the values of 0.36 ± 0.02 nJ (gyroid) and 0.43 ± 0.03 nJ (diamond), respectively, when compared to intrinsic epoxy resin (approximately 0.02 ± 0.002 nJ) with brittle characteristics. This enhanced property is attributed to the synergic effect of the deliberate structure with well-ordered nanonetwork texture and the toughening of BCP-based modifiers at the molecular level. In addition to the deliberate structural effect from the nanonetwork texture, the BCP modifier composed of epoxy-philic hard segment and epoxy-phobic soft segment led to dispersed soft-segment domains in the nanonetwork-structured epoxy matrix with superior interfacial strength for the enhancement of applied energy dissipation.

Inspired from ubiquitously found chiral polymers in living organisms, block copolymers composed of chiral entities (i.e., chiral block copolymers (BCPs*)) have emerged to engender chiral architectures via self-assembly. The solvent selectivity and polymer concentration play a pivotal role in the self-assembly of BCP* in solution, giving a wide variety of self-assembled textures from micellization, microphase separation, and crystallization. In this study, the formation of kinetic-controlled self-assembled unique topological nanostructures such as Moebius, figure-of-eight, and rectangular ribbons via microphase separation of BCP* in mixed solvents has been thoroughly substantiated through twisting and bending of a microphase-separated bilayer under appropriate conditions. The polymer concentration in mother liquid along with supersaturation did show apparent dependence on the obtained morphology. The formation of vesicles could be observed in the solution with a lower concentration region, whereas crystallization dominates at a higher concentration region, giving a window of concentration for the formation of microphase-separated topographic nanostructures in mixed solvents. By taking advantage of homochiral evolution from self-assembly, preferred helicity of forming Moebius ribbons can be obtained. In contrast to the single twist for the Moebius ribbons, multiple twisting can be fashioned, as evidenced by the formation of the figure-of-eight and rectangular ribbons with double twists and rationalized by the forming mechanisms from theories. This study may provide supplementary understanding of the morphological evolution from the self-assembly of BCPs in solution with kinetically controlled chiral superstructures.