The surface morphology and dynamic impact properties with rebounding and splashing of water droplet on phase separation and breath figure assisted electrospinning films

Green and effective fabrication of porous surfaces with adjustable cell structure by foaming at incomplete healed polymer-polymer interface

Porous surfaces of materials have shown huge potentialities for endowing materials with multifarious functions. Despite introducing gas-confined-barriers in supercritical CO₂ foaming technology is effective to weaken the gas escape effect and facilitate the preparation of porous surfaces, the differences in intrinsic properties between barriers and polymers result in bottlenecks like cell structure adjustment limitation and incompletely eliminated solid skin layers. This study undertakes a preparation approach for porous surfaces by foaming at incompletely healed polystyrene/polystyrene interfaces. In contrast with employing gas-confined-barriers reported before, the porous surfaces foamed at incompletely healed polymer/polymer interfaces show a monolayer, full-open cell morphology, and wide adjustable range in cell structures including cell size (120 nm∼15.68 μm), cell density (3.40 × 10⁵ cells/cm²∼3.47 × 10⁹ cells/cm²), and surface roughness (0.50 μm∼7.22 μm). Furthermore, the wettability of obtained porous surfaces depending on the cell structures is systematically discussed. Finally, a super-hydrophobic surface with hierarchical micro-nanoscale roughness, low water adhesion, and high water-impact resistance is built by depositing nanoparticles on a porous surface. Consequently, this study offers a clean and simple method to prepare porous surfaces with adjustable cell structures, which is expected to open a door to developing a new fabrication technique for micro/nano-porous surfaces.

Recent Progress of the Preparation and Application of Electrospun Porous Nanofibers

Electrospun porous nanofibers have gained a lot of interest recently in various fields because of their adjustable porous structure, high specific surface area, and large number of active sites, which can further enhance the performance of materials. This paper provides an overview of the common polymers, preparation, and applications of electrospun porous nanofibers. Firstly, the polymers commonly used to construct porous structures and the main pore-forming methods in porous nanofibers by electrospinning, namely the template method and phase separation method, are introduced. Secondly, recent applications of electrospun porous nanofibers in air purification, water treatment, energy storage, biomedicine, food packaging, sensor, sound and wave absorption, flame retardant, and heat insulation are reviewed. Finally, the challenges and possible research directions for the future study of electrospun porous nanofibers are discussed.

Design and synthesis of novel poly (aryl ether ketones) containing trifluoromethyl and trifluoromethoxy groups

The high-frequency and high-speed communication in the 5 G era puts forward requirements for the dielectric properties of polymers. Introducing fluorine into poly(ary ether ketone) can improve its dielectric properties. In this work, by introducing the fluorine group strategy, we successfully designed and synthesized three novel trifluoromethyl (-CF₃) or trifluoromethoxy (-OCF₃)-containing bisphenol monomers and their F-substitution PEK-based polymers (PEK-Ins). All these PEK-Ins exhibited good thermal, mechanical and dielectric properties. The T d5% of the three polymers is all higher than 520℃. The free volume fraction of novel polymers increased from 3.75% to 5.72%. Among the three polymers, exhibited the lowest dielectric constant of the films is 2.839, and the dielectric loss is 0.0048, ascribing to the increasing free volume. The Young's modulus of the polymer film is as high as 2.9 GPa and the tensile strength is as high as 84 MPa. PEK-Ins reduced the dielectric constant by introducing a low fluorine content. This study provides a new way to design PEK to synthesize low dielectric constant polymers.

Electrospun Porous Nanofibers: Pore−Forming Mechanisms and Applications for Photocatalytic Degradation of Organic Pollutants in Wastewater

Electrospun porous nanofibers have large specific surface areas and abundant active centers, which can effectively improve the properties of nanofibers. In the field of photocatalysis, electrospun porous nanofibers can increase the contact area of loaded photocatalytic particles with light, shorten the electron transfer path, and improve photocatalytic activity. In this paper, the main pore−forming mechanisms of electrospun porous nanofiber are summarized as breath figures, phase separation (vapor−induced phase separation, non−solvent−induced phase separation, and thermally induced phase separation) and post−processing (selective removal). Then, the application of electrospun porous nanofiber loading photocatalytic particles in the degradation of pollutants (such as organic, inorganic, and bacteria) in water is introduced, and its future development prospected. Although porous structures are beneficial in improving the photocatalytic performance of nanofibers, they reduce their mechanical properties. Therefore, strategies for improving the mechanical properties of electrospun porous nanofibers are also briefly discussed.

Superhydrophobicity and conductivity of polyester-conductive fabrics using alkaline hydrolysis

A superhydrophobic conductive fabric is developed to solve the problem of functional deterioration due to oxidation by air and water through alkaline hydrolysis and hydrophobic coating.