Fluorinated polymers are receiving more and more attention worldwide due to their unique chemical properties, and modified fluorinated polymers with different topologies are persued for enriching and enhancing their performance in a variety of application fields. In this work, main-chain-type semifluorinated graft copolymers are produced steadily in continuous tube reactors via photocontrolled step transfer-addition and radical-termination (START) polymerization and Cu(0)-mediated reversible deactivation radical polymerization (Cu(0)-RDRP) at room temperature for the first time. Specifically, semifluorinated alternating copolymer (AB)_nB is prepared by START polymerization of 1,6-diiodoperfluorohexane (A) and 1,7-octadiene (B) in the first quartz pipeline under irradiation with purple LED light at 20 °C. The (AB)_nB with periodic C―I bonds is then flowed into the second copper pipeline directly and acts as the macroinitiators for Cu(0)-RDRP of methyl acrylate (MA) to obtain corresponding graft copolymer (AB)_nB-g-PMA. This work provides a new strategy for continuous synthesis of fluorinated graft copolymer materials.

Combining the advantages of mechanochemiluminescence from 1,2-dioxetane and elastico-mechanoluminescence from ZnS particles, a new kind of mechanoluminescent polymer composites are developed. They can emit bright luminescence with two distinct colors at different strains, empowering a verstaile mechanochemical strategy for force sensing and damage detection at a wider force responsive range.

In recent years, the power conversion efficiency of organic solar cells (OSCs) and perovskite (PVSCs) has increased to over 19% and 25%, respectively. Meanwhile, the long-term stability of OSCs and PVSCs was also significantly improved with a better understanding of the degradation mechanism and the improvement of materials, morphology, and interface stability. As both the efficiency and lifetime of solar cells are approaching the commercialization limit, fabrication methods for large-area OSCs and PVSCs that can be directly transferred from lab to fab become essential to promote the industrialization of OSCs and PVSCs. Compared with the coating methods, inkjet printing is a mature industrial technology with the advantages of random digital patterning, excellent precision and fast printing speed, which is considered to have great potential in solar cell fabrication. Many efforts have been devoted to developing inkjet-printed OSCs and PVSCs, and much progress has been achieved in the last few years. In this review, we first introduced the working principle of inkjet printing, the rheology requirements of inks, and the behaviors of the droplets. We then summarized the recent research progresses of the inkjet-printed OSCs and PVSCs to facilitate knowledge transfer between the two technologies. In the end, we gave a perspective on inkjet-printed OSCs and PVSCs.

The conversion of perhydropolysilazane (PHPS) to silica at low temperature is beneficial for its application on thermally vulnerable substrates. In this work, it is demonstrated that (3-aminopropyl)triethoxysilane (APTES) has high catalytic efficiency for the low temperature conversion of PHPS and the catalytic mechanism of APTES was suggested. The influence of temperature and humidity on the catalytic conversion process was investigated, and it was found that PHPS can be rapidly converted to silica in 10 min at 80 °C with relative humidity of 90%. The achieved silica is mainly composed of SiNO₃/SiO₃OH and SiO₄ structure with O/Si of 1.74 and N content of 1%. As an approach to prepare inorganic coating, the low-temperature conversion method achieves a silica coating with low volume shrinkage of 0.86%, low roughness of R_a=0.293 nm, high nanoindentation hardness of 3.62 GPa and modulus of 30.06 GPa, which exhibits high potentials as protective coating for various materials even those vulnerable to high temperature.

Preparation of chemically recyclable polyesters by ring-opening polymerization (ROP) has made a considerable progress over the past few years. However, this method involves cumbersome synthesis and minimal functional diversity of cyclic monomers. Therefore, it is of great significance to develop novel polymerization methods for direct polymerization of commercially available monomers to prepare recyclable polyesters with versatile functionalities. In present work, we report dehydrogenative copolymerization of commercial α,ω-diols to afford high molecular weight chemically recyclable aliphatic copolyesters (65.7 kg·mol⁻¹) by using commercially available Milstein catalyst precursor. The thermal properties of the obtained copolymers could be finely tuned by simply adjusting the feeding ratio of two monomers. The incorporation of aliphatic or aromatic rings into polyester mainchain via copolymerization of 1,10-decanediol with 1,4-cyclohexanedimethanol and 1,4-benzenedimethanol could significantly improve the thermal properties of the resulting copolymers. More importantly, the obtained copolyesters were able to completely depolymerize back to original diols via hydrogenation by the same catalyst in solvent-free and mild conditions, thus offering a green and cost-effective route toward the preparation of widely used polyesters.

Introduction of asymmetric units into conjugated polymers is an important strategy to regulate the photophysical and electronic properties of polymers, as asymmetric units can not only regulate solubility and energy levels, but also molecular stacking and orientation, thus giving much higher optoelectronic properties. However, very few studies have been reported in this field. The semiconducting properties of conjugated polymers could be regulated through regioregularity adjustment. Here, we took the asymmetric thiophene/pyridine side group DPP as core and developed the regioregular monomer T-Py-DPP through three steps: alkyl chain introduction, tin monomer coupling and NBS double bromination. The T-Py-DPP monomer was polymerized into reg-PPyTDPP-2FBT with a head-to-head structure. The regioregularity of T-Py-DPP unit endowed reg-PPyTDPP-2FBT with backbone planarity, self-assembly orientation, network-like morphology and high crystallinity in films, thus the superior bipolar transport properties. The highest hole and electron mobilities of reg-PPyTDPP-2FBT were 0.93 and 0.57 cm²·V⁻¹·s⁻¹, respectively, with 40% improvement relative to the regiorandom polymer.

Combretastatin A4 phosphate (CA4P) is a potent vascular disrupting agent with good water solubility. However, it is only effective at high doses, which decreases clinical applicability. Herein, we designed stable CA4P polymeric nanoparticles (CA4P NPs) consisting of various cholesterol derivatives, and with a drug loading efficacy of 93%. The nanoparticles released CA4P in a sustained manner and achieved a 72% inhibition rate in the murine H22 liver tumor model, which was about 2.9-fold higher than that of free CA4P (24.6%). Furthermore, the carrier components of CA4P NPs were metabolized to arginine, cholesterol, ethanol and poly(ethylene glycol) in vivo; therefore, the CA4P NPs are safe and have significant potential for clinical translation.

Temperature-accelerated in vitro degradation was established to estimate the longevity of polyurethane applied for long-term implantation. However, the prediction did not correlate well with the data from clinical explants and the rationality of accelerated in vitro test is still in a controversial due to the deviation. To improve the accuracy of the in vitro prediction, the influence of hydrogen bonding (HB) on the accelerated hydrolysis of silicone based polyetherurethans (SPEUs) extended with three side chains. Combining the temperature-controlled FTIR and the physical properties after temperature-accelerated in vitro degradation, it was demonstrated that side chain could increase the degree of hydrogen bond dissociation at higher temperature, resulting in the decrease of the calculated activation energy (E_a) of hydrolysis. At low temperatures, changes in surface morphology and molar mass of PEUs are minimal and HB are less easily dissociated, which had barely impact on the hydrolysis resistance. It was proposed that the E_a will not be impacted and that the accuracy of prediction will be increased if the acceleration temperature is lower than 70 °C and HB change is less than 15%.

In recent years, flexible strain sensors have received considerable attention owing to their excellent flexibility and multifunctionality. However, it is still a great challenge for them to accurately monitor multi-model deformations with high sensitivity and linearity. In this study, the industrial insulating silk habotai was successfully converted into carbonized silk habotai (CSH) for use in strain sensors. A strain sensor created using CSH exhibited excellent sensing performance under multi-model deformations, including stretching, twist and bending. The maximum tensile strain was 434%. The gauge factors were 14.6 in the wide tensile range of 0%–400% with a high linearity of 0.959. In addition, the CSH strain sensor exhibited an extremely fast response time (110 ms) and could accurately detect bending (0°–180°) and torsional (0°–180°) strains. High durability and repeatability were observed for the multi-model strains. Finally, a new type of smart pillow was developed to accurately record head movement and breathing during sleep. The sensor may also be used for auxiliary training in table tennis. The proposed CSH strain sensor has shown great potential for applications in smart devices and human-machine interactions.

For decades, the preparation of polyisoprene rubber that can match the comprehensive properties of natural rubber (NR) has been pursued. While sacrificial bonds have been used to promote the strength and toughness of rubbers, little is known about their effects on fatigue resistance, which is important in dynamic environments. Herein, terminal block and randomly functionalized polyisoprene rubbers tethered with di-alanine, tri-alanine and tetra-alanine were prepared. The results showed that the flow activation energy, aggregates ordering and energy dissipation of the hydrogen-bonded aggregates increase with the elongation of oligopeptide length (XA, X=2, 3, 4), therefore resulting in enhanced mechanical strength and toughness of corresponding samples. Comparably, the tear strengths are barely affected by oligopeptide lengths in block samples, but promoted from dipeptide to tetrapeptide in random samples, probably due to the well dispersed oligopeptide aggregates. Most importantly, it is found that the tight binding aggregates of oligopeptides are critical for the excellent fatigue resistance, which is absent in polyisoprene and natural rubber. The loose aggregates dissociate and recombine repeatedly under cyclic loading and the tight aggregates keep the network integrated and robust. Interestingly, the largest hysteresis of PIP-4A-V with the longest oligopeptide length give the lowest heat generation, which is contrary to the traditional sacrificial bonds. Overall, the oligopeptide aggregates have repeatable energy dissipation properties and cycle life comparable to or even surpassing those of the linked proteins in NR, resulting in similar tensile strength, fracture toughness, and better fatigue resistance relative to NR. This deep insight on the role of oligopeptide aggregates is very useful for the engineering rubbers served in dynamic environments.

Thermoplastic polyimides (PIs) with shape memory potential have received growing attention in recent years. In this work, high-performance thermoplastic PIs were fabricated by introducing PIs with chain rigidity (r-PI) into PI with chain flexibility (f-PI). The influences of molecular chain entanglement and π-π interactions on their thermomechanical and shape memory properties were investigated. The degree of molecular chain entanglement was quantitively characterized based on dynamic mechanical analysis (DMA). The π-π interactions were investigated in detail by X-ray diffraction (XRD) and UV-Vis spectroscopy. It was found that the entanglement density increased and π-π interactions became stronger with the introduction of r-PI into f-PI, leading to the improvement of shape recovery. Moreover, a broad and increased glass transition temperature (T_g) was achieved, endowing the PIs with multiple shape memory properties. The synergistic effects of increased entanglement density and enhanced π-π interactions were beneficial to regulating interchain interactions and thereby achieving high shape memory performance of the PIs.

The formation of cocrystallization in two various conjugated components may endow the newly formed conjugated cocrystals with multiple functionalities and improved charge transport properties. However, compared to conjugated small molecules, this strategy is rather limitedly realized in conjugated polymers. Herein, a simple meniscus-assisted solution printing (MASP) strategy is utilized to achieve the cocrystallization in the blends of two conjugated polymers, i.e., poly(3-hexylthiophene) (P3HT) and poly(3-octylthiophene) (P3OT), and the cocrystalline structures are correlated closely to their charge mobilities. The P3HT/P3OT blends phase separate and crystallize individually in their drop-cast thin films. When subjecting the P3HT/P3OT blended solution to MASP, the confined solvent evaporation between two nearly parallel plates triggers them to cocrystallize progressively when accelerating the moving lower plate. The cocrystallization kinetics and the changes in P3HT/P3OT molecular structures are elucidated. Finally, these different crystalline structures of P3HT/P3OT blends are applied in organic field-effect transistors, imparting the cocrystallization-enhanced charge transport than respective P3HT and P3OT crystal domains. Such MASP method can be extended to craft cocrystals of other conjugated polymer blends for their diverse optoelectronic applications.

Carbon nanotube (CNT)/epoxy nanocomposites have a great potential of possessing many advanced properties. However, the homogenization of CNT dispersion is still a great challenge in the research field of nanocomposites. This study applied a novel dispersion agent, carboxymethyl cellulose (CMC), to functionalize CNTs and improve CNT dispersion in epoxy. The effectiveness of the CMC functionalization was compared with mechanical mixing and a commonly used surfactant, sodium dodecylbenzene sulfonate (NaDDBS), regarding dispersion, mechanical and corrosion properties of CNT/epoxy nanocomposites with three different CNT concentrations (0.1%, 0.3% and 0.5%). The experimental results of Raman spectroscopy, particle size analysis and transmission electron microscopy showed that CMC functionalized CNTs reduced CNT cluster sizes more efficiently than NaDDBS functionalized and mechanically mixed CNTs, indicating a better CNT dispersion. The peak particle size of CMC functionalized CNTs reduced as much as 54% (0.1% CNT concentration) and 16% (0.3% CNT concentration), compared to mechanical mixed and NaDDBS functionalized CNTs. Because of the better dispersion, it was found by compressive tests that CNT/epoxy nanocomposites with CMC functionalization resulted in 189% and 66% higher compressive strength, 224% and 50% higher modulus of elasticity than those with mechanical mixing and NaDDBS functionalization respectively (0.1% CNT cencentration). In addition, electrochemical corrosion tests also showed that CNT/epoxy nanocomposites with CMC functionalization achieved lowest corrosion rate (0.214 mpy), the highest corrosion resistance (201.031 Ω·cm²), and the lowest porosity density (0.011%).

The aging of natural rubber (NR) at high temperatures will seriously affect its service lifetime in many key applications. In the present work, the changes in microstructure and mechanical properties of semi-efficient vulcanized NR/carbon black (CB) vulcanizates during thermo-oxidative aging at high temperatures (150−200 °C) and a moderate temperature (95 °C) were compared. At high temperatures, a two-stage aging behavior, which was characteristic of a first rapid decline and then a continuous rise in the crosslinking density (v_e), was identified and was found to be closely related to the depletion behavior of antioxidants. The surface cracking behavior observed in the second stage of high-temperature aging was discussed in terms of the grafting reaction of macromolecular radicals on CB particles and thermal expansion. In contrast, the aging of NR at moderate temperatures was much mild, which featured a continuous increase in v_e and an oxidation mechanism dominated by peroxy radicals attacking double bonds. In general, the mechanical properties of NR vulcanizates during high-temperature aging depended on the competition effects of structural evolution in the crosslinked network and oxidation-induced chain scission.

In this work, we study the poly(3,4-ethylenedioxythiophene):poly(styrene sulfonate) (PEDOT:PSS) structure in aqueous dispersion with small-angle X-ray scattering (SAXS). In-depth structure analysis is achieved based on a set of complementary and sophisticated algorithms, which provide not only shape and packing of chains but also 3D structure of the colloids. The structure information of the PEDOT chain was extracted from the well-known Guinier, Porod and pair distance distribution function (PDDF) analysis of the SAXS data, while the 3D modelling was achieved with the DAMMIF and DAMAVER programs in ATSAS software package. To the best of our knowledge, we first establish the 3D model of the PEDOT:PSS colloids’ structure that will help people to understand the supramolecular assembly in aqueous dispersion, which sheds light on the solution structure study of polymers that are widely used in daily life.

Conjugated microporous polymers have excellent skeleton structures but poor electrical conductivity limits their applications in microwave absorption. To solve this problem, a strategy of molecular expansion and confining polymerization is proposed in this work to synthesize conductive hyper-crosslinked conjugated microporous polymer. The topology of the conjugated microporous polymer is changed into a three-dimensional skeleton structure with high specific surface area by using molecular expansion technique, and the controlled growth of polypyrrole in the channel constructs a unique network structure. The balance of excellent composite backbone structure, proper conductivity, attenuation capability and impedance matching enable the material to exhibit electromagnetic wave absorption performance. As a result, with low filler loading of 10 wt%, a strongest reflection loss of −52.68 dB and a maximum effective bandwidth of 5.76 GHz. Additionally, CST simulations of the radar scattering cross section have been carried out to verify the excellent material properties. This study provides new concepts for new conductive polymers and broadens the application of hyper-crosslinked conjugated microporous polymer in the field of electromagnetic wave absorption.