Nanofiltration has been attracting great attention in alleviating the global water crisis because of its high efficiency, mild operation, and strong adaptability. Over decades, it remains a challenge to break the upper limit of performance and establish the formation-structure-property relationship for nanofiltration membranes. This feature article summarizes our recent progress in the preparation of high-performance thin-film composite (TFC) nanofiltration membranes, focusing on the mussel-inspired deposition method and the optimized interfacial polymerization (IP). By accelerating the oxidation of polydopamine and equilibrating the rate of aggregation and deposition processes, the mussel-inspired deposition method realizes the rapid and uniform formation of selective coatings or nanofilms. Diverse deposition systems endow the selective layer with rich chemical structures and easy post-functionalization, highlighting its potential in water treatment. As for optimizing the conventional IP, the rapid polycondensation of amine and acid chloride groups is slowed down to enable the controllability of IP at the water-organic interface. The homogeneity and integrity of the TFC membranes are improved by constructing a uniform reaction platform and introducing a viscous medium to control the amine diffusion, which facilitates the water permeability and promotes the separation efficiency. We have proposed a series of practical strategies for improving TFC membranes and might provide more inspiration for other nanofiltration techniques.

Three alternating conjugated polymers, namely PFTP, PCzTP, and PSiTP, which combine a thieno[3,4-b]pyrazine (TP) unit with different benzene-based donor units such as 9,9-dioctylfluorene, 9-heptadecyl-9H-carbazole and 5,5-dioctyl-5H-dibenzo[b,d]silole, were synthesized in good yield (>85%) and high molecular weight up toM_n=5.82×10⁴ via direct arylation polymerization (DArP). All the resultant polymers exhibit moderate bandgap of about 1.80 eV and strong deep red/near-infrared emitting in the solid state. Among them, the PSiTP-based electroluminescence (EL) devices with an architecture of ITO/PEDOT:PSS/PTAA/emitting layer/TPBi/LiF/Al give the best performance with a maximum luminance of 2543 cd/m² at 478 mA/cm². This work expands the application scope of high-performance conjugated polymers which can be synthesized by DArP.

Benzobisthiazole polymer with resonance-assisted hydrogen bonds (RAHBs) has been synthesized for both organic field-effect transistor and polymer solar cell applications. The properties of the hydrogen bonded polymer are compared with the reference polymer without RAHBs. Single-crystal X-ray diffraction analyses of the building block reveal that the RAHB interactions are formed between the carbamate hydrogen and imine nitrogen of the thiazoles. The hydrogen donor and acceptor are connected by π-conjugated molecular framework and the hydrogen-bridged quasi aromatic rings lock the conformation of the building block. The building block adopted a layered sandwich packing in crystal instead of slipped herringbone stacking which was often found in the crystal of benzobisthiazole derivatives. The polymer PCBTZ-TT with RAHBs showed deeper HOMO/LUMO energy level (about 0.2 eV) than reference polymer. The PCBTZ-TT demonstrated the hole mobility of 0.96 cm²·V⁻¹·s⁻¹ in field-effect transistor devices and achieved power conversion efficiency of 13.6% in solar cell devices with Y6 as acceptor without any additive.

Near-infrared light (NIR) triggered transdermal drug delivery systems are of great interest due to their on-demand drug release, which enable to enhance drug treatment efficiency as well as reduce side effect. Herein, a NIR-triggered microneedle (MN) patch array has been fabricated through depositing the photothermal conversion agent and anti-diabetic drug-loaded polymer vesicles with upper critical solution temperature (UCST) into dissolvable polymer matrix. The UCST-type polymer has a clearing point temperature of 41 °C and the drug-loaded polymer vesicles present excellent NIR-triggered and temperature responsive drug release behavior in vitro due to the disassociation of polymer vesicles upon NIR irradiation. After applying MNs to diabetic rats, significant hypoglycemic effect is achieved upon interval NIR irradiation and the blood glucose concentration can decrease to normal state for several hours, which enables to achieve the goal of on-demand drug release. This work suggests that the NIR-triggered MN drug release device has a potential application in the treatment of diabetes, especially for those requiring an active drug release manner.

Nature has been inspiring material researchers to fabricate biomimetic functional devices for various applications, and shape-memory polymer materials (SMPMs) have received tremendous attention since the promising intelligent materials possess more advantages over others for the fabrication of biomimetic functional devices. As is well-known, SMPMs can be stimulated by heat, electricity, magnetism, pH, solvent and light. From the viewpoint of practical applications, ultraviolet (UV)-visible (Vis)-near infrared (NIR) light-responsive SMPMs are undoubtedly more advantageous. However, up to now, UV-Vis-NIR light-deformable SMPMs by combining photothermal and photochemical effects are still rarely reported. Here we designed a UV-Vis-NIR light-deformable SMP composite film via incorporating a liquid crystal (LC) mixture and graphene oxide (GO) into a shape-memory polyurethane matrix. The elongated composite films exhibited interesting photomechanical bending deformations with different light-triggered mechanisms, (1) photochemically induced LC phase transition upon UV exposure, (2) photochemically and photothermally induced LC phase transition upon visible-light irradiation, (3) photothermally triggered LC phase transition and partial stress relaxation upon low-intensity NIR exposure. All the deformed objects could recover to their original shapes by high-intensity NIR irradiation. Moreover, the biomimetic circadian rhythms of acacia leaves and the biomimetic bending/spreading of fingers were successfully achieved, which could blaze a way in the field of biomimetic functional devices due to the excellent light-deformable and shape-memory properties of the SMP composite films.

Polyetherketoneketone (PEKK) is a new evolving polymeric material, and is considered as another important member of the polyaryletherketone (PAEK) family in addition to polyetheretherketone (PEEK). Hot compression molding can be used to compact and consolidate the PEKK products, where the temperature and pressure play key roles to affect the molecular mobility, entanglement and crystallization, and thus the mechanical properties of PEKKs. In this study, a preheating treatment was introduced in the compression molding, and it is found that such preheating is very essential to avoid the formation of crystal Form II, based on the increased chain entanglement. Molecular dynamics simulations revealed that the molecular mobility is always suppressed when a compression is applied. Therefore, by increasing the entanglement via the preheating and maintaining such entanglement in the consequent compression molding, strong and tough PEKK materials were obtained, with a negligible fraction of crystal Form II.

In this contribution, we reported a novel synthesis of block copolymer networks composed of poly(ε-caprolactone) (PCL) and polyethylene (PE) via the co-hydrolysis and condensation of α,ω-ditriethoxylsilane-terminated PCL and PE telechelics. First, α,ω-dihydroxyl-terminated PCL and PE telechelics were synthesized via the ring-opening polymerization of ε-caprolactone and the ring-opening metathesis polymerization of cyclooctene followed by hydrogenation of polycyclooctene. Both α,ω-ditriethoxylsilane-terminated PCL and PE telechelics were obtained via in situ reaction of α,ω-dihydroxyl-terminated PCL and PE telechelics with 3-isocyanatopropyltriethoxysilane. The formation of networks was evidenced by the solubility and rheological tests. It was found that the block copolymer networks were microphase-separated. The PCL and PE blocks still preserved the crystallinity. Owing to the formation of crosslinked networks, the materials displayed shape memory properties. More importantly, the combination of PCL with PE resulted that the block copolymer networks had the triple shape memory properties, which can be triggered with the melting and crystallization of PCL and PE blocks. The results reported in this work demonstrated that triple shape memory polymers could be prepared via the formation of block copolymer networks.

This study investigated the effects of natural rubber (NR) and an organic peroxide on the rheological properties, mechanical properties, morphology, and bubble stability during film blowing of poly(lactic acid) (PLA). The NR and peroxide contents were varied from 0 wt% to 25 wt% and 0 wt% to 0.5 wt%, respectively. The results confirmed that the presence of well-dispersed NR could significantly improve the toughness, elongation at break, and processability of PLA films, where the optimal amount of NR was 15 wt%. For the reactive blending with peroxide, a suitable peroxide content for good film toughness and clarity was 0.03 wt%, while the higher content of 0.1 wt% could provide slightly higher processability. These contents are considered much lower than that in the PLA system (without NR), which required up to 0.5 wt% peroxide. The rheological studies indicated that the melt strength, the storage modulus (G') and complex viscosity (η^*) at low frequency could be correlated with good film blowing processability of the PLA/NR films at low gel contents. These parameters failed to correlate in the films having high gel contents as the deformation rate experienced by each test was different leading to the different levels of response to the type and amount of gels.

A biodegradable blend foaming material of poly(butylene adipate-co-terephthalate) (PBAT)/poly(propylene carbonate) (PPC) was successfully prepared by chemical foaming agent and screw extrusion method. First, PBAT was modified by bis(tert-butyl dioxy isopropyl) benzene (BIBP) for chain extension, and then the extended PBAT (E-PBAT) was foamed with PPC using a twin (single) screw extruder. By analyzing the properties of the blends, we found that Young's modulus increased from 58.8 MPa of E-PBAT to 244.7 MPa of E-PBAT/PPC 50/50. The viscosity of the polymer has a critical influence on the formation of cells. Compared with neat PBAT (N-PBAT), the viscosity of E-PBAT increased by 3396 Pa·s and E-PBAT/PPC 50/50 increased by 8836 Pa·s. Meanwhile, the dynamic mechanical analysis (DMA) results showed that the storage modulus (E') at room temperature increased from 538 MPa to 1650 MPa. The various phase morphologies (“sea-island”, “quasi-co-continuous” and “co-continuous”) and crystallinity of the blends affected the spread velocity of gas and further affected the foaming morphology in E-PBAT/PPC foam. Therefore, through the analysis of phase morphology and foaming mechanism, we concluded that the E-PBAT/PPC 70/30 component has both excellent strength and the best foaming performance.

In spite of the impending flattening of Moore's law, the complexity and size of the systems we are interested in keep on increasing. This challenges the computer simulation tools due to the expensive computational cost. Fortunately, advanced theoretical methods can be considered as alternatives to accurately and efficiently capture the structural and thermodynamic properties of complex inhomogeneous fluids. In the last decades, classical density functional theory (cDFT) has proven to be a sophisticated, robust, and efficient approach for studying complex inhomogeneous fluids. In this work, we present a pedagogical introduction to a broadly accessible open-source density functional theory software package named "an advanced theoretical tool for inhomogeneous fluids" (Atif) and of the underlying theory. To demonstrate Atif, we take three cases as examples using a typical laptop computer: (i) electric double-layer of asymmetric electrolytes; (ii) adsorptions of sequence-defined semiflexible polyelectrolytes on an oppositely charged surface; and (iii) interactions between surfaces mediated by polyelectrolytes. We believe that this pedagogical introduction will lower the barrier to entry to the use of Atif by experimental as well as theoretical groups. A companion website, which provides all of the relevant sources including codes and examples, is attached.