Soil environment on earth contains a variety of ions, which are expected to play a vital role in the biodegradation of plastics discarded in the environment. In this work, poly(butyleneadipate-co-terephthalate) (PBAT) is employed as a model biodegradable plastic to study the specific ion effects on the enzymatic degradation of polyester plastics. The results show that the specific ion effects on the enzymatic degradation rate of the PBAT films and on the catalytic rate constant for the enzymatic hydrolysis of the ester bonds are strongly dependent on temperature and ionic strength. Both the enzymatic degradation rate and catalytic rate constant decrease following the trends Na⁺ > K ⁺ > Ca ²⁺ and Cl⁻ > SO ₄²⁻ > NO ₃⁻ for cations and anions, respectively, indicating that the ion-specific enzymatic degradation of the PBAT films is closely correlated with the specific ion effects on enzymatic hydrolysis of the ester bonds. Our study shows that the specific ion effects on the enzyme activity can be understood by taking into account the ion-specific cation-anion interaction, ionic dispersion force, salting-out effect and salting-in effect. This study of specific ion effects on the enzymatic hydrolysis of the ester bonds and the resultant enzymatic degradation of the PBAT films would offer us a new clue to develop new biodegradable, environmentally friendly synthetic plastics.

Cellulose is one of the most abundant natural polymers in the nature, which has many attractive advantages, such as renewability, biodegradability, and biocompatibility. However, due to the strong hydrogen bond network and hierarchical structure, cellulose is extremely difficult to be dissolved and processed. More recently, a class of novel eco-friendly solvents, ionic liquids, have been found to be able to efficiently dissolve cellulose, providing a versatile platform for cellulose processing and functionalization. Herein, we highlight recent advances in efficiently fabricating functional cellulose derivatives via the homogeneous chemical modification and developing all-biomass materials via controlling the dissolution-regeneration process in ionic liquids. The effective and environmentally-friendly utilization of cellulose not only reduces dependence on fossil resources but also protects the environment.

Mixing two or more polymers to produce the “polymer alloy” is one of the most versatile and economical strategies for developing new polymeric materials. The compatibility between polymer components largely determines the comprehensive performance of polymer blend. More recently, a type of unique surface partitioned materials, Janus particles, has been proposed to act as a novel interfacial compatibilizer for polymer blends. Such Janus particles integrates the amphipathicity of diblock copolymer and interfacial stabilization of nanoparticles, displaying a significant superiority in comparison with molecular compatibilizers for a wide range of polymer blends. In this review, we mainly focus on the compatibilizing effects of Janus nanofillers of various morphologies, including spherical, snowman-like, and two-dimensional nanosheets, on polymer blends. We shed light on the impacts of compatibilization of Janus particles on phase morphologies, mechanical properties, and functionalities of polymer blends. This review could provide a guidance for designing an effective Janus particle compatibilizer to develop high-performance polymer blends.

The impact of ring polymer length N and the influence of interchain and intrachain interactions on the size and dynamic behaviors of ring polymers, including the structural relaxation time τ_R and self-diffusion coefficientD, remain poorly understood at present due to a lack of systematic studies with relatively large N values. This work addressed this issue by applying dynamic Monte Carlo simulations with independently tuned interchain and intrachain interactions to investigate the size and dynamics of the ring melts with chain lengths over a wide range of 0.2N_e≤N≤80N_e (N_e is the entanglement length of corresponding linear chains) under different topological constraints, including all-crossing and inter-crossing systems. We found that it was inappropriate to treat the unknotting constraint free energy of the ring chains in the melts as the free energy contributed by the excluded volume interactions of polymers in a good solvent. Scaling exponents of 2.5 and 1.5 reflecting the N-dependence of τ_R were obtained for long ring chains in non-crossing and intra-crossing systems, respectively, suggesting that the ring chains behaved as individual clusters and exhibited Zimm-like dynamics in intra-crossing systems. A single scaling exponent of −2 reflecting the N-dependence of D was obtained for ring chains in non-crossing and intra-crossing systems, indicating that the intrachain constraints affected only the value of D, and had little influence on the scaling relationship between D and N. Furthermore, the extended Stokes-Einstein relation broke down for the ring chains in the non-crossing and intra-crossing systems because the structural relaxation and translational diffusion were decoupled for the short ring systems, while both the translational diffusion and rotational relaxations, as well as diffusion at short and long time scales, were decoupled for long ring systems.

As one of the major challenges in tumor chemotherapy, multidrug resistance typically correlates with the poor drug penetration within tumor tissues and drug efflux by the ATP-driven efflux pumps in tumor cells. Herein, we design a kind of near-infrared (NIR) light- and acidity-activated micellar iPUTDN nanoparticle for mitochondria-targeting doxorubicin (DOX) delivery to combat DOX resistance in small-cell lung cancer. While the PEGylated iPUTDN nanoparticles can keep stealth in blood circulation, NIR irradiation at the tumor region can peel off the PEG shell from the nanoparticles, and the exposed iRGD can facilitate deep tumor penetration of the nanoparticles. After being internalized by DOX-resistant H69AR cells, the poly(β-aminoester)s (PAE)-based nanoparticles can release the triphenylphosphonium (TPP)-conjugated DOX (TDOX) into the cytosol, which can further accumulate in mitochondria with the aid of TPP. Consequently, the mitochondrial membrane potential and ATP content are both reduced in DOX-resistant H69AR cells. The in vivo therapeutic results show that TDOX-loaded nanoparticles with the aid of NIR light irradiation can effectively suppress the DOX-resistant small-cell lung cancer without noticeable adverse effects.

Under laser irradiation, photothermal therapy (PTT) effectively ablates tumors above 50 °C. However, hyperthermia can cause additional damage due to the inevitable heat spread to surrounding healthy tissue. Herein, nanoparticles named as GI@P NPs were designed for enhanced PTT with heat shock protein 90 (HSP90) inhibition at temperatures below 50 °C to achieve optimal cancer therapy and avoid surrounding damage. GI@P NPs were done by co-loading Garcinia cambogia acid (GA) and photosensitizer IR783 in polymer PLG-g-mPEG to form a nanomedicine, where IR783 with excellent photoacoustic (PA) signal acted as an excellent photothermal therapeutic agent that converted the laser energy into heat to kill tumor cells, GA was used as antitumor drug for chemotherapy and an inhibitor of HSP90 to overcome the heat resistance of tumors for efficient cryo-photothermal therapy, and PLG-g-mPEG can encapsulate IR783 and GA to increase biocompatibility and accumulate effectively in the tumor. After GI@P NPs were injected into the mice, we could observe that the PA signals gradually increased in the tumor region and showed the strongest PA signals at 12 h. Under laser irradiation, the tumor temperature of the mice could raise to about 43.5 °C, and the tumor was significantly inhibited after long-term monitoring by PA imaging. As a result, gentle PTT produced by GI@P NPs exhibited good antitumor effects at relatively low temperature and minimized nonspecific thermal damage to normal tissues. The GI@P NPs as nanomedicine enriched our understanding of various applications of polymeric carriers, especially in the biomedical field.

Mechanofluorochromic materials that render sensitive fluorescence color/pattern change upon mechanical stimuli have drawn extensive attention. However, traditional mechanofluorochromism relies on the chemical transformations of mechanophores, but their types are quite few. It remains challenging to develop mechanofluorochromic materials with customized fluorescence color changing response. Herein, a generally applicable strategy is proposed to present a class of double-layer mechanofluorochromic hydrogels based on the facile integration of two different-colored fluorescent hydrogels. Due to the UV transmittance change of top layer under Poisson’s effect, the emission intensity ratio of the upper and lower hydrogels exhibits a strain-dependent change, resulting in a force-triggered overlapping color variation. Both the UV transmittance of top layer and the fluorescence emission of bottom layer can be readily modulated to enrich the variety of mechanofluorochromism. Besides, the bottom layer is available to be printed by ion inks to fabricate patterned double-layer fluorescent hydrogel, holding great potential to design flexible mechanofluorochromic platforms for smart display and information encryption.

Nonfused ring electron acceptors (NFREAs) have attracted much attention due to their concise synthetic routes and low cost. However, developing high-performance NFREAs with simple structure remains a great challenge. In this work, a simple building block (POBT) with noncovalently conformational locks (NoCLs) was designed and synthesized. Single-crystal X-ray study indicated the presence of S···O NOCLs in POBT, thus enabling it to possess a coplanar conformation comparable to that of fused-ring CPT. Two novel NFREAs based on CPT and POBT were developed, namely TT-CPT and TT-POBT, respectively. Besides, TT-POBT possessed a smaller Stokes shift and a reduced reorganization energy compared with TT-CPT, indicating the introduction of S···O NoCLs can enhance the molecular rigidity even if simplifying the molecular structure. As a result, the TT-POBT-based PSC device afforded an impressive power conversion efficiency of 11.15%, much higher than that of TT-CPT counterpart (7.03%), mainly resulting from the tighter π-π stacking, improved and balanced charge transport, and more favorable film morphology. This work demonstrates the potential of the simple building block POBT with NoCLs towards constructing low-cost and high-performance NFREAs.

In the current global crisis of antibiotic resistance, persuit of an effective multi-pathway collaborative approach to enhance antibacterial activity is urgently needed. Here, a kind of hyperbranched polyacetal quaternary ammonium (Hyper-ace-QA) with efficiently antibacterial function were synthesized by a succession of efficient click strategies. The high molecular weights can be obtained just after UV irradiation for 3 h, and the grafting ratio can be easily adjusted through controlling solvent system, molar ratio, and temperature. Cytotoxicity studies indicated that Hyper-ace-QA had good biocompatibility and can be used as a potential antibacterial dressing. More importantly, after in situ encapsulation of bioactive curcumin drugs into the hyperbranched intramolecular cavities, the acid-liable acetal linkers within the hyperbranched backbone made the loading antibacterial drugs rapidly release with pH- or bacterial-responsive behaviors since many bacteria can produce acids at the infection site by the combined actions of immune response and bacterial metabolism. Therefore, the integration of quaternary ammonium characteristics and pH-triggered curcumin release could facilitate the antibacterial activity against gram-positive Staphylococcus aureus. This work represents a synergistic strategy on offering important guidance to rational design of multifunctional antimicrobial vehicles, which would be promising therapeutic alternatives for first aid treatment of wound infection in critical situations.

The structure of side chains of π-conjugated segments is a critical factor determining living crystallization-driven self-assembly (CDSA), a versatile platform to generate fiber-like nanostructures with precise length and composition. Herein, we design and synthesize three block copolymers (BCPs) containing same corona-forming poly(N-isopropyl acrylamide) (PNIPAM) segment, but different core-forming π-conjugated oligo(p-phenylene vinylene) (OPV) with linear pentyl (l-OPV), racemic 2-methyl butyl (r-OPV) and stereo-regular chiral (S)-2-methyl butyl (c-OPV) side chains, respectively. By using these BCPs of l-OPV-b-PNIPAM₄₇, r-OPV-b-PNIPAM₄₇ and c-OPV-b-PNIPAM₄₇ as model, we aim to get a deep insight into how steric and stereo-regular effect induced by branched alkyl side chains of OPV segment affects the living CDSA. The results showed that l-OPV-b-PNIPAM₄₇ exhibits typical characteristics of self-seeding and seeded growth of living CDSA to give uniform fiber-like micelles of controlled length. On the contrary, r-OPV-b-PNIPAM₄₇ and c-OPV-b-PNIPAM₄₇ with branched racemic and stereo-regular chiral alkyl side chains are more prone to self-nucleation during the micellar elongation to give short and polydisperse fiber-like micelles. The obvious self-nucleation during the micellar elongation of r-OPV-b-PNIPAM₄₇ and c-OPV-b-PNIPAM₄₇ is due to the increase of steric repulsion with OPV units induced by branched alkyl side chains, not the stereo-irregular effect of racemic alkyl side chains.

Self-assembly of π-conjugated compounds into supramolecular polymers has received considerable attention because of their intrinsic scientific interests and technological applications. As compared to π-conjugated rods, discotics, and macrocycles, propeller-shaped π-conjugated molecules have been less exploited to form long-range-ordered supramolecular polymers. Herein a novel type of supramolecular polymers has been constructed on the basis of propeller-shaped triphenylamine cyanostilbenes. The designed compound adopts nucleation−elongation cooperative mechanism for the supramolecular polymerization process, because of the participation of three-fold hydrogen bonds between the neighbouring monomers. The supramolecular polymeric state displays amplified chirality and enhanced emission than those in the monomeric state. The resulting supramolecular polymers exhibit severe emission quenching upon addition of 2,6-dinitrotoluene, ascribed to photoinduced electron transfer from the triphenylamine cyanostilbenes to the explosive analyte. The current study proves the feasibility to supramolecular polymerize propeller-like π-conjugated molecules, serving as a promising type of explosive sensor owing to their guest encapsulation and signal amplification capabilities.

Nanofiltration (NF) membranes as high selective separators are appealing for molecular sieving, which still remains a great challenge for the mixed dyes with same charge. In this study, cellulose acetate (CA) membranes were firstly aminated by ethylene imine polymer (PEI), and then the thin film of metal organic frameworks (MOFs) were constructed onto aminated CA membrane through forward-diffusion, slow crystallization and in situ growth of FeCo-Prussian blue (FeCo-PB) crystallization layers. The designed PB@CA composite NF membrane shows an ideal rejection for Congo red (CR)/methyl orange (MO) mixture solution, with 99.7%±0.2% for CR and 33.5%±2% for MO. In addition, the composite NF membrane demonstrated good efficiency for photocatalytic degradation of organic fouling (permeability recovery ratio was up to 92%) due to the active FeCo-PB micro-cubes. Thus, this work provides a practical strategy to prepare MOFs mediated thin film composite nanofiltration membrane for precise molecular sieving and catalytic antifouling performances.