Molecular Design of an Interfacially Active POSS-Bottlebrush Block Copolymer for the Fabrication of Three-Dimensional Porous Films with Unimodal Pore Size Distributions through the Breath-Figure Self-Assembly

Light-Induced Self-Assembled Polydiacetylene/Carbon Dot Functional "Honeycomb"

The design of functional supramolecular assemblies from individual molecular building blocks is a fundamental challenge in chemistry and material science. We report on the fabrication of "honeycomb" films by light-induced coassembly of diacetylene derivatives and carbon dots. Specifically, modulating noncovalent interactions between the carbon dots, macrocyclic diacetylene, and anthraquinone diacetylene facilitates formation of thin films exhibiting a long-range, uniform pore structure. We show that light irradiation at distinct wavelengths plays a key role in the assembly process and generation of unique macro-porous morphology, by both initiating interactions between the carbon dots and the anthraquinone moieties and giving rise to the topotactic polymerization of the polydiacetylene network. We further demonstrate utilization of the macro-porous film as a photocatalytic platform for water pollutant degradation and as potential supercapacitor electrodes, both applications taking advantage of the high surface area, hydrophobicity, and pore structure of the film.

Novel hybrid composites based on double-decker silsesquioxanes functionalized by methacrylate derivatives and polyvinyl alcohol as potential materials utilized in biomedical applications

The use of diverse biomaterials for regenerative medicine is constantly evolving. Therefore, looking for easy-to-scale-up materials in terms of preparation, less complex composition, and featuring structural and chemical stability seems justified. In this work, we report the preparation of double-decker silsesquioxane-based (DDSQ-based) composites, which, according to our best knowledge, have never been used as biomaterials. A family of methacrylate-substituted DDSQs was obtained starting from the previously reported hydroxyalkyl double-decker silsesquioxanes. In the resulting hybrids, methacrylate groups are attached to each other's lateral silicon atoms of DDSQ in trans positions, providing an excellent geometry for forming thin layers. In contrast to pure organic methacrylates, the covalent bonding of methacrylate derivatives to inorganic silsesquioxane core improves mechanics, cell adhesion, and migration properties. Furthermore, to increase the hydrophilicity of the resulting DDSQ-based hybrids, polyvinyl alcohol (PVA) was added. The entire system forms an easy-to-obtain two-component (DDSQ-PVA) composite, which was subjected without any upgrading additives to biological tests later in the research. The resulting biomaterials fulfill the requirements for potential medical applications. Human fibroblasts growing on prepared hybrid composites are characterized by proper spindle-shaped morphology, proliferation, and activation status similar to control conditions (cells cultured on PVA), as well as increased adhesion and migration abilities. The obtained results suggest that the prepared biomaterials may be used in regenerative medicine in the future.

Fabrication of Adsorption-Type Hierarchical Functional Films by Using a Facile Swollen Based Breath Figure Method

The morphology transition from primary to hierarchical adsorption-type microporous domains of amphiphilic block copolymer (BCP) honeycomb-structured films is demonstrated by a facile swollen based breath figure (BF) method. The characteristic parameters of poly(4-vinylpyridine)-block-polystyrene (P4VP-b-PS) hierarchical micro- and submicro-porous films can be controlled by changing the length of segments or subsequent swelling conditions. A plausible mechanism is demonstrated in this research. A typical amphiphilic BCP with very low volume content of hydrophilic blocks (f_P4VP ≤ 0.050) can efficiently stabilize water droplets and inherently assist in the formation of morphology transition. This BCP film can be used for Cr(VI) removal from wastewater, which additionally has enormous potential application in the field of novel optical devices, soft lithography, size-selective separation, etc. This article is protected by copyright. All rights reserved.

Recent advances on porous interfaces for biomedical applications

Porous structures on solid surfaces prepared artificially through the water droplet template method have the features of easy operation, low cost and self-removal of templates, and thus are widely applied in the fields of medicine, biomedicine, adsorption, catalysis, and separation, optical and electronic materials. Due to their tunable dimensions, abundant selection of materials, mechanical stability, high porosity, and enlarged pore surface, the formed porous interfaces show specific significance in bio-related systems. In this study, recent achievements related to applications of porous interfaces and a focus into biological and medical-related systems are summarized. The discussion involves the preparation of porous interfaces, and porous interface-induced cell behaviors including culture, growth, proliferation, adhesion, and differentiation of cells. The inhibitory effect of bacteria and separated features of microorganisms supported by porous interfaces, the immobilization of biomolecules related to proteins, DNA and enzymes, and the controllable drug delivery are also discussed. The summary of recent advances pointed out in the study, are suggestive of insights for motivating unique potential applications including their extension to porous interfaces in biomedical materials.

Control of the pore size of honeycomb polymer film from micrometers to nanometers via substrate-temperature regulation and its application to photovoltaic and heat-resistant polymer films

Honeycomb porous polystyrene (PS) films with an aspect ratio of pore depth to pore diameter at approximately 1.0 were fabricated using the breath figure (BF) method. Two modes of water droplet coalescence in the pore growth were observed in real-time by optical microscopy. Pore size significantly increases with the increase in humidity and the decrease in substrate temperature. The porous pattern could emerge even at room temperature under high humidity of 80%. Boiling point and solvent density significantly influence the pore distribution and pore depth. Chloroform and tetrahydrofuran achieve more uniform hexagonal patterns than benzene and dichloromethane. Subsequently, to obtain nanometer porous PS film, the fast-evaporation BF process was designed by regulating the gradient substrate temperature and evaporation time, and porous mesoscopic PS film was obtained. The minimum pore diameter and corresponding pore depth are about 120 nm and 27 nm, respectively. Finally, the fast-evaporation BF process was applied to the honeycomb film formation of photovoltaic polymer poly(3-hexylthiophene) (P3HT), and the heat-resistant polymers polysulfone (PSF) and polyimide (PI).