Rapid progress in nanotechnology allows us to develop a large number of innovative wearables such as activity trackers, advanced textiles, and healthcare devices. However, manufacturing processes for desirable nanostructure are usually complex and expensive. Moreover, materials used for these devices are mainly derived from nonrenewable resources. Therefore, it poses growing problems for living environment, and causes incompatible discomfort for human beings with long‐time wearing. Here, a self‐powered cellulose fiber based triboelectric nanogenerator (cf‐TENG) system is presented through developing 1D eco‐friendly cellulose microfibers/nanofibers (CMFs/CNFs) into 2D CMFs/CNFs/Ag hierarchical nanostructure. Silver nanofibers membrane is successfully introduced into the cf‐TENG system by using CMFs/CNFs as template, which shows excellent antibacterial activity. Enabled by its desirable porous nanostructure and unique electricity generation feature, the cf‐TENG system is capable of removing PM2.5 with high efficiency of 98.83% and monitoring breathing status without using an external power supply. This work provides a novel and sustainable strategy for self‐powered wearable electronics in healthcare applications, and furthermore paves a way for next‐generation flexible, biocompatible electronics.

Click chemistry is one of the most powerful strategies for constructing polymeric soft materials with precise control over architecture and functionality. In this review, we provide a comprehensive summary of the state-of-the art for synthesizing functional polymers and their expanding range of applications. The synthetic and mechanistic aspects are discussed for key reactions that fulfill "click" requirements and their applications in construction of macromolecules with linear, branched, and other complex architectures are described.

No abstract

A versatile and scalable strategy is reported for the rapid generation of block copolymer libraries spanning a wide range of compositions starting from a single parent copolymer. This strategy employs automated and operationally simple chromatographic separation that is demonstrated to be applicable to a variety of block copolymer chemistries on multigram scales with excellent mass recovery. The corresponding phase diagrams exhibit increased compositional resolution compared to those traditionally constructed via multiple, individual block copolymer syntheses. Increased uniformity and lower dispersity of the chromatographic libraries lead to differences in the location of order–order transitions and observable morphologies, highlighting the influence of dispersity on the self-assembly of block copolymers. Significantly, this separation technique greatly simplifies the exploration of block copolymer phase space across a range of compositions, monomer pairs, and molecular weights (up to 50000 amu), producing materials with increased control and homogeneity when compared to conventional strategies.

Three phenylenediamine (PD) monomers, o-phenylenediamine (OPD), m-phenylenediamine (MPD), and p-phenylenediamine (PPD), were used to prepare the functionalized graphene (PD/rGO) networks. The results obtained from a series of chemical, thermal, and rheological analyses elucidated the mechanism of the covalent bonding and the existence of cross-linked graphene networks. The measured XRD patterns and molecular dynamic calculations discovered that those PPD and MPD molecules could enlarge graphene interlayer spacing to 1.41 and 1.30 nm, respectively, while OPD molecules were disorderly bonded or nonbonded to the basal planes of graphene layers, resulting in small and variable interlayer distances. The loadings of PD monomers were optimized to achieve superior supercapacitor performance. Electrochemical study showed that PPD/rGO exhibited the largest specific capacitance of 422 F/g with excellent cycling stability and low charge transfer resistance. The large variations in the capacitance values among PD/rGO networks with different PD monomers were explained by the difference in the graphene nanostructures, reversible redox transitions, and charge transfer characteristics. Particularly, density function theory calculations were adopted to compare electronic properties of the PD/rGO composites, including formation energy, electron density distribution, HOMO energy levels, and electron density of states near the Fermi level.

Self-healing polymer electrolytes are reported with light-switchable conductivity based on dynamic N-donor ligand-containing diarylethene (DAE) and multivalent Ni2+ metal-ion coordination. Specifically, a polystyrene polymer grafted with poly­(ethylene glycol-r-DAE)­acrylate copolymer side chains was effectively cross-linked with nickel­(II) bis­(trifluoromethanesulfonimide) (Ni­(TFSI)2) salts to form a dynamic network capable of self-healing with fast exchange kinetics under mild conditions. Furthermore, as a photoswitching compound, the DAE undergoes a reversible structural and electronic rearrangement that changes the binding strength of the DAE–Ni2+ complex under irradiation. This can be observed in the DAE-containing polymer electrolyte where irradiation with UV light triggers an increase in the resistance of solid films, which can be recovered with subsequent visible light irradiation. The increase in resistance under UV light irradiation indicates a decrease in ion mobility after photoswitching, which is consistent with the stronger binding strength of ring-closed DAE isomers with Ni2+. 1H–15N heteronuclear multiple-bond correlation nuclear magnetic resonance (HMBC NMR) spectroscopy, continuous wave electron paramagnetic resonance (cw EPR) spectroscopy, and density functional theory (DFT) calculations confirm the increase in binding strength between ring-closed DAE with metals. Rheological and in situ ion conductivity measurements show that these polymer electrolytes efficiently heal to recover their mechanical properties and ion conductivity after damage, illustrating potential applications in smart electronics.

Bicyclo[3.3.1]nonane (BCN) polycations were synthesized by the reaction of the bivalent electrophile thiabicyclo[3.3.1]nonane dinitrate with a series of simple bis(pyridine) nucleophiles. Oligomers of moderate chain length were formed in a modular approach that tolerated the inclusion of functionalized and variable-length linkers between the pyridine units. Post-polymerization modification via copper-catalyzed azide-alkyne cyloaddition was enabled by the inclusion of terminal alkyne groups in these monomers. Most of the resulting polymers, new members of the polyionene class, inhibited the growth of bacteria at the μg/mL level and killed static bacterial cells at polymer concentrations of tens of ng/mL, with moderate to good selectivity with respect to lysis of red blood cells. While resistance to the BCN polymers was developed only very slowly over multiple passages, a degradable version of the polycation was observed to make E. coli cells more susceptible to other quaternary ammonium based antimicrobials. Solid substrates (glass and crystalline silicon) covalently functionalized with a representative BCN polycation were also able to repetitively kill bacteria in solution at high rates and with cleaning by simple sonication between exposures.

A new family of modular, fragmentable oligo- and polycations has been developed based on the reactions of 9-thiabicyclo[3.3.1]­dichloride and related compounds with substituted dipyridyl nucleophiles by an anchimeric assistance mechanism. Each bond-forming event in this condensation polymerization process generates a positive charge in the main chain. Product lengths were found to be dependent on the reactivity of the electrophile, which was tunable by changing the nature of the leaving group β to sulfur. The monomers were easily synthesized, and the resulting readily available polymers were found to be highly efficient binders of nucleic acid. They exhibited properties of cytotoxicity and DNA transfection expected of such polycationic materials, but with interesting structure–activity differences that remain to be explored. The polycations decomposed by hydrolysis at rates dependent on the leaving group ability of the pyridyl unit, which correlated roughly with the pK a of its conjugate acid. Polymer decomposition occurs simultaneously throughout the length of the chains, rather than from the ends; the decomposition products were tested and found to be only minimally toxic to cultured cells.