As the high calibre candidate of lightweight and flexible solar cells, polymer solar cells (PSCs) have made tremendous progress in recent years. However, the active photovoltaic materials in PSCs are mainly synthesized by metal-mediated coupling reaction requiring harsh reaction conditions, multiple-step synthesis, and cumbersome purification, which is not cost-efficient and may bring toxicity concerns. It is not favorable to the production of photovoltaic polymers and PSC devices on a large scale, and therefore unsuitable for the PSCs industrialization. Direct arylation coupling reaction via aromatic C―H bonds activation enables the synthesis of conjugated polymers under mild conditions and simultaneously reduces synthetic steps, difficulty, and toxic reaction byproducts. This review provides an overview of the history of preparing representative photovoltaic polymers utilized in PSCs through direct arylation reactions and discusses the activity and selectivity of C―H bonds in typical building blocks under different reaction conditions. Especially, the impact of direct arylation condition on defect formation and photovoltaic performance of the photovoltaic polymers is addressed and compared with conventional Stille coupling methods.

Perylene-3,4-(dicarboxylic monoimide)-9,10-(dicarboxylic monoanhydrate) (PIA) is one key intermediate to construct functionalized perylene diimides (PDIs) for various applications. However, the difficulty in synthesizing chlorinated PIA hinders the study of chlorinated PDI-based materials. Although chlorination has been widely used to modify the properties of organic semiconductors. We successfully synthesize chlorinated PIA via a simple hydrolysis reaction using LiOH as the base, then a PDI dimer connected at the imide position, N-di-PDI-4Cl, is synthesized as an application example of chlorinated PIA. The heavily chlorinated PDI dimer exhibits deeper energy levels, slightly blue-shifted UV-Vis absorption compared to the non-chlorinated analogue. In addition, the photovoltaic performance of N-di-PDI-4Cl is characterized. This study paves one easy way to synthesize chlorinated PIA and its more delicate derivatives.

Quasi solid-state succinonitrile (SN)-based polymer electrolytes have emerged for lithium-metal batteries due to their excellent ion-conductivity at room temperature, wide electrochemical stability window (ESW, usually >5 V). However, the practical application of these solid SN-based polymer electrolytes is hampered by the flammability and the inherent instability of SN to Li-metal anode. In this work, solid SN-based polymer electrolytes were prepared with succinonitrile, ethoxylated trimethylolpropane triacrylate (ETPTA), triethyl phosphate (TEP) and fluoroethylene carbonate for Li-metal battery via in situ polymerization method. The SN-based polymer electrolytes with 5 wt% triethyl phosphate and FEC showed good nonflammability, superior ion-conductivity as high as 1.01×10⁻³ S/cm, and wide ESW of 5.41 V. This SN-based polymer electrolyte also exhibited excellent interfacial compatibility to lithium metal anode. And it also delivered a high specific capacity of 156 mAh/g at 0.2 C at ambient temperature, and presented stable cycling at 1.0 C with a specific capacity retention of 98.4% after 1000 cycles. This work provides an alternative and simple strategy to realize the practical application of the solid-state SN-based polymer electrolyte.

It remains a challenging task to achieve ring-opening (co)polymerization (ROP) of macrolactones. Hence, we synthesized a series of Al-based catalysts and systemically investigated the effect of N-containing substituent on the sidearms on ROP of macrolactones. Al3 possessing N-methyl group could effectively achieve controlled ROP of pentadecalactone (PDL) and macro(di)lactone ethylene brassylate (EB) in combination with BnOH, furnishing polyethylene-like PPDL and PEB with M_w up to 90.3 and 321 kg/mol, respectively. Random copolymerization of PDL and small-ring lactones ε-caprolactone (ε-CL) and δ-valerolactone (δ-VL) could prepare random copolyesters with tailored T_m in the range of 57−94 °C by controlling the ratios of PDL and ε-CL, δ-VL. More importantly, well-defined block copolyesters could be obtained by sequential adding PDL and ε-CL, δ-VL, which have been proved by GPC-MALLS, DSC and ¹³C-NMR.

Without any type of surfactant or dispersing agent, precipitation polymerization has great superiorities in both polymer synthesis and applications. In the present work, the polymerization of vinyl chloride (VC), n-butyl acrylate (BA), and vinyl acetate (VAc) are conducted in the precipitation polymerization system and series of their random terpolymers poly(vinyl chloride-co-n-butyl acrylate-co-vinyl acetate) (PCBV) are synthesized successfully. The effects of various polymerization conditions, including solvent polarity, temperature, initiator concentration, and monomer feed ratios on the polymerization kinetics, number-average molecular weight (M_n), and terpolymer composition are investigated systematically. The solvent and the monomer feed ratio are crucial factors not only for the polymer morphology, but also for the reaction kinetic. In the non-polar solvent such as n-hexane, the PCBV displays particle morphology when the composition of BA ratio lower than 10 wt%. Otherwise, the PCBV forms a uniform polymer phase and precipitates out from the mixture. In the polar solvent, e.g., dimethyl carbonate (DMC) and ethanol, the PCBV polymer maintains a slurry state either in low or in high monomer feed ratio. Impressively, VC based ternary copolymer that obtained in n-hexane has much lower M_n (<20 kDa) and much higher BA units mass fraction (>40 wt%) compared with emulsion and suspension polymerization. Additionally, the terpolymer can be easily separated by simple centrifugation.

Polyurethane is widely used for its versatility in design and range of performance. Self-healing and recyclable dynamic polyurethane networks have attracted extensive attention due to their potential to extend service life and ensure safety in use, as well as to promote sustainable use of resources. Developing green and environment-friendly methods to obtain this material is an interesting and challenging task, as the majority of current dynamic polyurethane networks utilize the solution polymerization method. The use of solvents makes the processes complicated, harmful to environment, and increase the cost. Poly(oxime-urethanes) (POUs) are emerging dynamic polyurethanes and show great potential in diverse fields, such as biomaterials, hot melt adhesives, and flexible electronics. In this study, we utilized the solubility properties of dimethylglyoxime in raw material poly(ethylene glycol) to prepare POUs through bulk polymerization for the first time. This method is simple, convenient and cost-efficient. Simultaneously, copper ion coordination improves POUs strength and dynamic properties, with mechanical strength up from 0.54 MPa to 1.03 MPa and self-healing recovery rate up from 85.5% to 91.8%, and activation energy down from 119.6 kJ/mol to 95.4 kJ/mol. To demonstrate the application of this technology, self-healing and stretchable circuits are constructed from this dynamic polyurethane network.

The integration of high mechanical toughness, impact strength as well as excellent flame-retardant properties toward epoxy resins (EPs) have always been a dilemma. The inadequate overall performance of EPs severely restricts their sustainable utilization in engineering aspects over long-term. Herein, a new bio-based agent (diglycidyl ether of magnolol phosphine oxide, referred as DGEMP) derived from magnolol (classified as lignan), extracted from natural plants Magnolia officinalis, was successfully synthesized and further employed as a flame-retardant reactive additive to diglycidyl ether of bisphenol A (DGEBA). As demonstration, the composite resin, DGEBA/15DGEMP (15 wt% DGEMP), achieved an Underwriters Laboratories-94 V-0 rating with a high limiting oxygen index (LOI) value (41.5%). In cone calorimeter tests, it showed that heat release and smoke production were effectively inhibited during combustion, wherein the peak heat release rate (PHRR) value of DGEBA/15DGEMP was reduced by 50% compared to neat DGEBA. Additionally, it exhibited a superior tensile strength (82.8 MPa), toughness (5.11 MJ/m³) and impact strength (36.5 kJ/m²), much higher than that of neat DGEBA (49.7 MPa, 2.05 MJ/m³ and 20.9 kJ/m²). Thus, it is highly anticipated that DGEMP imparts significantly improved mechanical and fire-retarded properties to conventional EPs, which holds a great potential to address the pressing challenges in EP thermosets industry.

Nanotheranostics, which combine the therapeutic and diagnostic functions in one integrated system, have received extensive attentions in cancer treatments because they enable non-invasive diagnosis, tumor-targeted drug delivery, and real-time monitoring of therapeutic response. However, due to the high systemic toxicity of commonly used chemotherapeutics, current treatment still has limitations. Herein, to simultaneously achieve safe cancer therapy and therapeutic response monitoring, an iodinated prodrug strategy was proposed. 2,3,5-Triiodobenzoic acid (TIBA) was used to modify both paclitaxel (PTX) and the polymeric vehicle, so that the encapsulation efficiency of PTX could be increased and the systemic toxicity could be reduced. As-prepared prodrug nanoparticles could accumulate passively in the tumor site and promptly release loaded drugs in response to the overexpressed GSH in cancer cells, which then caused efficient cell cycle arrest and apoptosis like that of the parent PTX. With this rational design, safe and efficient antitumor therapy and real-time computer tomography (CT) imaging could be simultaneously realized, facilitating potential CT imaging-guided therapy of metastatic breast cancer.

A linear fluorinated benzocyclobutene-type monomer (4F-bis-BCB) was facilely synthesized by a one-step copper-catalyzed etherification reaction and a simple precipitation post-purification method. Moreover, a series of BCB-based polymeric low-dielectric (low-k) materials were obtained by the thermal-induced ring-opening copolymerization of 4F-bis-BCB with divinyl tetramethyl disiloxane-bisbenzocyclobutene (DVS-BCB) monomer and further simple thermal curing at high temperature (200–300 °C). The resultant fully cured materials demonstrated excellent low dielectric properties at high frequency of 10 GHz (dielectric constant (D_k)<2.6, dielectric loss (D_f)<1.57×10⁻²), great hydrophobicity (water contact angle >116°), ultra-low water absorption (<0.19% after soaked in water at room temperature for 60 h) and excellent planarization ability (surface roughness<0.56 nm of 3 μm-thick film). Overall, this new fluorinated BCB-type monomer provides us an alternative for the facile preparation of low- k polymeric materials and exhibits great potential for future applications in high-frequency communication and three-dimensional high-density packaging technologies.

Fluorosurfactants are the key ingredients in the formulations of aqueous film-forming foams (AFFFs) for extinguishing flammable liquids, thus developing high-efficient and low-toxic fluorosurfactants is desirable in AFFFs application. Herein, a series of hyperbranched polymeric fluorosurfactants (HPFs) were successfully synthesized through sequentially modifying hyperbranched polyethylenimine (PEI) with the hydrophilic poly(ethylene glycol) (PEG) chains and the hydrophobic C6/C4-based perfluoroalkyl chains, which were verified by FTIR, ¹H- and ¹⁹F-NMR. The surface tensions of all the HPFs in water were measured, and the corresponding physicochemical parameters were interpreted. It was found that the surface activities of HPFs could be tuned through adjusting the ratio of PEG to perfluoroalkyl chains, the length of perfluoroalkyl chains, the molecular weight of PEI core, but not the PEG chain length. In the binary mixture of HPFs with the commercial small molecule fluorosurfactant Capstone^TM 1157 (C1157), a strong synergism led to the elevation of surface activity, which was attributed to the efficient encapsulation of C1157 guests by the compact hyperbranched HPFs as the hosts. The utilization of HPF/C1157 as fluorosurfactant ingredients in AFFF formulations could realize much higher fire-extinguishing efficiency towards flammable oils than the control AFFFs prepared from the polymeric Capstone^TM 1460 or the neat C1157.

Although there has been rapid advancement in piezoelectric sensors, challenges still remain in developing wearable piezoelectric sensors by a one-step, continuous and environmentally friendly method. In this work, a 1D flexible coaxial piezoelectric fiber was directly fabricated by melt extrusion molding, whose core and sheath layer are respectively slender steel wire (i.e., electrode) and PVDF (i.e., piezoelectric layer). Moreover, such 1D flexible coaxial piezoelectric fiber possesses short response time and high sensitivity, which can be used as a self-powered sensor for bending and vibration sensing. More interestingly, such 1D flexible coaxial piezoelectric fiber (1D-PFs) can be further endowed with 3D helical structure. Moreover, a wearable and washable motion monitoring system can be constructed via braiding such 3D helical piezoelectric fiber (3D-PF) into commercial textiles. This work paves a new way for developing 1D and 3D piezoelectric fibers through a one-step, continuous and environmentally friendly method, showing potential applications in the field of sensing and wearable electronics.

3D printing silicone elastomer has demonstrated great potential in diverse areas such as medical devices, flexible electronics and soft robotics. It is of great value to investigate how to improve the mechanical properties, including tensile strength and elongation at break of printed parts. In this work, a light curing system that can be applied in silicone elastomer 3D printing is explored, which is composed of vinyl terminated polysiloxane as the macromer and thiol containing polysiloxane as the crosslinking agent, and a chain extension reaction is also introduced into this light curing system via the addition of the chain extender dithiol molecules, and a light curing system accompanied with chain extension is designed and realized based on the thiol-ene click reaction mechanism. After reinforced with silica fillers, the obtained light curing system can endow the light curing silicone elastomer with better mechanical properties under the condition of a lower viscosity of the precursor, the tensile strength and elongation at break can reach 525.5 kPa and 601%, respectively. This light curing system provides a feasible method to solve the contradiction between the viscosity of the precursor and the mechanical properties of the light curing elastomer in the digital light processing (DLP) 3D printing field.

Traditional silicone materials have poor mechanical properties, poor interfacial adhesion and lack the ability to be reprocessed or recycled. Herein, we developed a novel strategy of incorporating dynamic noncovalent bonds (2-amino-4-hydroxy-6-methylpyrimidine (UPy)) into side chain of silicone backbones to construct supramolecular silicone poly(urea-urethane) (SSPu) coatings with excellent mechanical performance, strong interfacial adhesion and multiple time recycling capability. Impressively, the prepared SSPu is endowed with simultaneously enhanced stiffness (272.0±23.2 MPa) and toughness (8.0±2.0 MJ·m⁻³). Besides, SSPu shows strong interfacial adhesion (up to 9.0±1.3 MPa) to diverse substrate (stainless steel, aluminum, copper, epoxy and glass) with long term stability. Moreover, SSPu exhibits excellent multi-recyclability and reusability without significantly decrease of its performance. In addition to the abovementioned features, the enrichment of siloxane backbones in the surface layer endows SSPu with robust repellency to water/oil. Our strategy provides a powerful route to fabricate a new multifunctional silicone elastomer. It is highly anticipated that our strategy can effectively extend the service life of silicone coating which can be applied in a wide variety of areas including self-cleaning, antifouling.

Poly(glycolic acid) (PGA) is derived from glycolide obtained by fermenting pineapples or sugarcane, which has excellent gas barrier properties and a small carbon footprint. PGA is a potential substitute for the current aluminum-plastic composite films used in high barrier packaging applications. However, its poor ductility and narrow processing window limit its application in food packaging. Herein, poly(butylene succinate-co-butylene adipate) (PBSA) was used to fabricate PGA/PBSA blend films through an in situ fibrillation technique and blown film extrusion. Under the elongational flow field used during the extrusion process, a unique hierarchical structure based on the PBSA nanofibrils and interfacially oriented PGA crystals was obtained. This structure enhances the strength, ductility and gas barrier properties of the PGA/PBSA blend film. In addition, an epoxy chain extender (ADR4468) was used as a compatibilizer to further enhance the interfacial adhesion between PGA and PBSA. 70PGA/0.7ADR exhibited a very low oxygen permeability (2.34×10⁻⁴ Barrer) with significantly high elongating at break (604.4%), tensile strength (47.4 MPa), and transparency, which were superior to those of petroleum-based polymers. Thus, the 70PGA/0.7ADR blown films could satisfy the requirements for most instant foods such as coffee, peanuts, and fresh meat.

Epoxidation of the carbon-carbon double bonds on unsaturated rubber macromolecules can produce novel modified rubber species with special properties, and construct eco-friendly crosslinking pathway via the reaction of epoxide groups to solve the problems brought by conventional sulfur vulcanization system. In this contribution, a novel modified product of isobutylene isoprene rubber (IIR), epoxy-functionalized IIR (EIIR) was successfully prepared by in situ epoxidation technique for the first time, and the crosslinking of EIIR was achieved by the reaction of oxirane groups with maleic anhydride (MAH) without additional additives. The reaction conditions for preparing EIIR were optimized through systematic research on the epoxidation process. Under optimal condition, the degree of epoxidation of the rubber reached around 99% without side reactions. The obtained EIIR/carbon black composites cured by MAH had excellent mechanical properties comparable to those of IIR composites. More importantly, compared with IIR composites, the air-tightness of the EIIR composites was improved by about 50%, and the flexural fatigue life of first-level cracks and sixth-level cracks was increased by several times. The significant improvement of these properties is of great significance for the application safety and energy saving of IIR materials.