Silicon (Si) is a promising anode material to replace the broadly adopted graphite due to its high capacity and abundant source. However, Si anodes suffer from severe problems of huge volume change (∼300%), and the commonly used binders like poly­(vinylidene fluoride) (PVDF) cannot accommodate such changes. Here, we report a tough block copolymer PVDF-b-Teflon (PTFE) binder that can coalesce pulverized Si and thus enhance the stability of Si anodes. The suspension copolymerization of vinylidene fluoride and tetrafluoroethylene produces elastic PVDF-b-PTFE with large breaking elongations of >250% and high viscosity as well as high ionic conductivity and thermal stability. We show that 5 wt % of the binder forms elastic cobweb structures in the electrode matrix that can effectively coalesce Si particles and conductive agents together, enabling long cycling stability (>250 cycles) and high rate performance (1 C) for electrodes at a commercial-level Si loading of 1 mg·cm–2. The findings point out to a promising strategy for developing highly elastic and tenacious binders for electrodes with large volume changes during the electrochemical reactions.

A series of antibiofouling amphiphilic conetwork (APCN) coatings combined with zwitterionic features are engineered by surface zwitterionization of spontaneously segregated poly­(N,N-dimethylaminoethyl methacrylate) (PDMAEMA) segments, where this dual-mode surface integration of both passive and active modes improves the entire antifouling efficiency against the adsorption of proteins and a widespread marine fouling organism (Phaeodactylum tricornutum). A clear difference in surface morphology and topography before and after surface zwitterionization is ascribed to the transformation of PDMAEMA to carboxlbetaine zwitterion, which promotes the phase segregation and simultaneously accelerates the migration of hydrophilic segments toward the surface. The surface morphology evolved with hydrophilic content, and the variation trend of surface roughness before and after surface zwitterionization is exactly opposite under different hydrophilic content. With regard to structure–antibiofouling relationships, the zwitterionic surface with heterogeneous morphology as well as higher zwitterion content exhibits superior antibiofouling efficiency. This design provides a novel methodology for the development of heterogeneous and zwitterionic antibiofouling conetwork, which will not only act as a breakthrough for the design and synthesis of next generation of efficient and eco-friendly antibiofouling coating but also expand the synthesis method of APCN so as to explore its application fields.

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Drawing to change the structural properties and cyclization behaviors of the polyacrylonitrile (PAN) chains in crystalline and amorphous regions is carried out on PAN and PAN/carbon nanotube (CNT) composite fibers. Various characterization methods including Fourier transform infrared spectroscopy, differential scanning calorimetry, X-ray diffraction and thermal gravimetric analysis are used to monitor the structural evolution and cyclization behaviors of the fibers. With an increase of the draw ratio during the plasticized spinning process, the structural parameters of the fibers, i.e. crystallinity and planar zigzag conformation, are decreased at first, and then increased, which are associated with the heat exchange rate and the oriented-crystallization rate. A possible mechanism for plasticized spinning is proposed to explain the changing trends of crystallinity and planar zigzag conformation. PAN and PAN/CNT fibers exhibit various cyclization behaviors induced by drawing, e.g., the initiation temperature for the cyclization (Ti) of PAN fibers is increased with increasing draw ratio, while Ti of PAN/CNT fibers is decreased. Drawing also facilitates cyclization and lowers the percentage of β-amino nitrile for PAN/CNT fibers during the stabilization.

Novel photocurable ternary polymer networks were prepared by incorporating N-(4-hydroxy-3-methoxybenzyl)-acrylamide (HMBA) into a cross-linked thiol-ene network based on poly(ethylene glycol)diacrylate (PEGDA) and (mercaptopropyl)methylsiloxane homopolymers (MSHP). The ternary network materials displayed bactericidal activity against Escherichia coli and Staphylococcus aureus and reduced the attachment of marine organism Phaeodactylum tricornutum. Extensive soaking of the polymer networks in aqueous solution indicated that no active antibacterial component leached out of the materials, and thus the ternary thiol-ene coating killed the bacteria by surface contact. The surface structures of the polymer networks with varied content ratios were studied by sum frequency generation (SFG) vibrational spectroscopy. The results demonstrated that the PDMS Si-CH groups and mimic-capsaicine groups are predominantly present at the polymer-air interface of the coatings. Surface reorganization was apparent after polymers were placed in contact with DO: the hydrophobic PDMS Si-CH groups left the surface and returned to the bulk of the polymer networks, and the hydrophilic PEG chains cover the polymer surfaces in DO. The capasaicine methoxy groups are able to segregate to the surface in an aqueous environment, depending upon the ratio of HMBA/PEGDA. SFG measurements in situ showed that the antibacterial HMBA chains, rather than the nonfouling PEG, played a dominant role in mediating the antibiofouling performance in this particular polymer system.