Recent years have witnessed the rapid developments of self-healing coatings because they can protect materials from diverse risks and are able to autonomously heal after being physically damaged. Here, a universal yet facile method is reported with high time and cost efficiency to fabricate transparent water-enabled self-healing coatings on various substrates by precipitating hydrogen-bonded tannic acid (TA)-polyethylene glycol (PEG) complexes in aqueous solution. The precipitated complexes coalesce to form uniform and transparent coatings on the substrates; after drying, mechanically robust coatings are obtained. TA endows such coatings with strong adhesion to a wide range of substrates and admirable antioxidant properties. Repeatable self-healing of the coatings is realized by simply exposing them to water or humid environment. Furthermore, these coatings can be readily erased by soaking them in basic solution, if needed.

Mussel-inspired chemistry has attracted widespread interest in the surface modification of polymer membranes. We have previously demonstrated a dopamine (DA) assisted codeposition process of polyethyleneimine onto polypropylene microfiltration membranes (PPMMs) for surface hydrophilization. In this work, we further investigate the effects of PEI molecular weight and DA/PEI mass ratio on the codeposition process and membrane performance. The results indicate that only low-molecular-weight PEI bring a distinct promotion in both surface wettability and water permeation flux for PPMMs. On the other hand, either excess DA or PEI is detrimental to the surface hydrophilicity of the studied membranes. The optimized PEI molecular weight is 600 Da and the corresponding mass ratio is 1:1 for the surface hydrophilization of PPMMs. These results are beneficial to understand those codeposition processes of dopamine with other polymers. © 2016 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2016, 133, 43792.

Mussel-inspired polydopamine (PDA) deposition offers a promising route to fabricate multifunctional coatings for various materials. However, PDA deposition is generally a time-consuming process, and PDA coatings are unstable in acidic and alkaline media, as well as in polar organic solvents. We report a strategy to realize the rapid deposition of PDA by using CuSO₄/H₂O₂ as a trigger. Compared to the conventional processes, our strategy shows the fastest deposition rate reported to date, and the PDA coatings exhibit high uniformity and enhanced stability. Furthermore, the PDA-coated porous membranes have excellent hydrophilicity, anti-oxidant properties, and antibacterial performance. This work demonstrates a useful method for the environmentally friendly, cost-effective, and time-saving fabrication of PDA coatings.

Mussel-inspired polydopamine (PDA) deposition offers a promising route to fabricate multifunctional coatings for various materials. However, PDA deposition is generally a time-consuming process, and PDA coatings are unstable in acidic and alkaline media, as well as in polar organic solvents. We report a strategy to realize the rapid deposition of PDA by using CuSO₄/H₂O₂ as a trigger. Compared to the conventional processes, our strategy shows the fastest deposition rate reported to date, and the PDA coatings exhibit high uniformity and enhanced stability. Furthermore, the PDA-coated porous membranes have excellent hydrophilicity, anti-oxidant properties, and antibacterial performance. This work demonstrates a useful method for the environmentally friendly, cost-effective, and time-saving fabrication of PDA coatings.

Isoporous separation membranes have received considerable attention because of the high-resolution performance and energy-saving characteristics. Isoporous membranes prepared by the breath figure method rely on special substrates such as water and ice because solid substrates such as polyethylene terephthalate films, which are widely used in commercial processes, often lead to nonthrough pores. In this work, it is found that highly ordered through-pore membranes can be fabricated on hydrophilic glass surface when using polymers that are able to form ordered membranes at low concentrations. On the basis of this finding, a facile strategy is proposed to fabricate isoporous membranes on various solid substrates by introducing a water-soluble polymer interlayer. The multifunctional interlayer promotes the spreading of membrane-forming solutions, enables the formation of through pores, and simplifies the transfer to macroporous supports to form composite membranes. The versatility of the proposed strategy is verified by using different substrates including highly hydrophobic polytetrafluoroethylene film and using different water-soluble polymers as the interlayer. Furthermore, the high-resolution separation performance of the isoporous composite membranes has been demonstrated by the filtration of yeasts under gravitational pressure.

In biological systems, disulfide bonds are formed efficiently under mild conditions without the release of harmful byproducts. Inspired by nature, we report a biomimetic polydopamine (PDA) catalyst for oxidative thiol coupling. This reaction was accelerated with only a small amount of PDA particles in neutral, weakly alkaline, and even weakly acidic aqueous media at room temperature under an air atmosphere. The catalytic particles were facilely separated and were reused without a decrease in activity. The entire process is totally biofriendly, including the synthesis of the PDA particles. This route is especially useful for the synthesis of pharmaceutical molecules.

Fluorescence-switch-based logic devices are very sensitive compared with most of the reported devices based on UV/Vis absorption systems. Herein, we demonstrate that a simple molecule, 5,10,15,20-tetra-(4-aminophenyl)porphyrin (TAPP), shows protonation-induced multiple emission switches through intramolecular charge transfer and/or aggregation-caused quenching. Highly sensitive INHIBIT and XOR logic gates can be achieved by combining the intermolecular assembly with the intramolecular photoswitching of diprotonated TAPP (TAPPH₂²⁺). In addition, molecular simulations have been performed by DFT for a better understanding of the emission-switching processes.

Development in the area of glycosylated membranes has been actively pursued in the past few years. This kind of promising biomimetic material is inspired by cell membranes. The recent surge of interest in these glycosylated membranes stems from their widespread number of applications to many areas in science and technology. With the glycosylation strategy, membrane separation properties, such as flux and antifouling, are greatly improved. Moreover, the ability to modulate biocompatibility, protein recognition, separation of biomolecules, enzyme immobilization, cell culture, and microorganisms capture are important in a variety of biological and medical applications. This review focuses on the recent progress in the preparation of these glycosylated membranes and highlights their applications. © 2013 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014, 131, 39658.

Polypropylene/calcium carbonate (CaCO₃) composite nonwoven meshes were prepared on the basic principle of biomineralization by using a facile alternate soaking process (ASP) within 20 min. Negatively charged poly(acrylic acid) brushes, which can induce CaCO₃ nucleation, were first tethered onto the fiber surface of polypropylene nonwoven meshes via UV-induced graft polymerization. ASP procedure was followed to mineralize CaCO₃ particles on the fiber surface and to form the composite nonwoven meshes. Fourier transform infrared spectroscopy/attenuated total reflectance, field emission scanning electron microscope, equipped X-ray spectroscope, and X-ray diffraction were used to characterize the prepared composite meshes. The mineral cover density increased with the ASP cycles, and it progressively increased for the relative content of calcite in the crystalline part of the mineral layer as well. Contact angle measurements indicate that the as-prepared composite nonwoven meshes were endowed with superhydrophilicity and underwater superoleophobicity, thus they showed prominent application prospects in wastewater treatment and oil/water separation. © 2013 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014, 131, 39897.

Thermally induced phase separation (TIPS) has been developed to prepare porous membranes. The porous structures are mainly dependent on diluents adopted in the TIPS process. We obtained two typical morphologies of poly(vinylidene fluoride) (PVDF) membranes using cyclohexanone (CO) and propylene carbonate (PC) as diluents, respectively. SEM observation displays that porous spherulites are formed from PVDF/CO system, whereas smooth particles result from PVDF/PC system. The TIPS processes of these two systems have been investigated in detail by optical microscope observation and temperature-dependent FTIR combined with two-dimensional infrared correlation analysis. Rapid crystallization of PVDF can be seen around 110 °C in the PVDF/CO system, which is consistent with the results of temperature-dependent FTIR spectra. The spectral evolution indicates a transform of PVDF from amorphous to α-phase after 110 °C. The ν_s(CO) band at 1712 cm⁻¹ narrows and the ν_s(CF) band at 1188 cm⁻¹ shifts to 1192 cm⁻¹ before crystallization, which implies the destruction of interaction between PVDF and CO. In contrast, the PVDF/PC system shows slow crystallization with all-trans conformation assigned to β-phase and γ-phase below 60 °C but no obvious change of polymer−diluent interaction. We propose two mechanisms for the different phase behaviors of PVDF/CO and PVDF/PC systems: a solid−liquid phase separation after destruction of polymer−diluent interaction in the former, and a liquid−liquid phase separation process coupled with rich-phase crystallization in the later. This work may provide new insight into the relationship among morphologies, crystal forms, and phase separation processes, which will be helpful to adjust membrane structure. © 2013 Wiley Periodicals, Inc. J. Polym. Sci., Part B: Polym. Phys. 2013, 51, 1438–1447

A series of poly(γ-alkyl α L-glutamate)s with different alkyl groups were synthesized by the ring opening polymerization of corresponding α-amino acid N-carboxyanhydrides. The characteristics of these polyglutamate surfaces were evaluated by attenuated total reflectance Fourier transform infrared spectroscopy spectra, water contact angle, water absorption, protein adsorption, and platelet adhesion measurements. Changing the length of the alkyl side chain provides a unique opportunity to study the influence of carbon number in the alkyl group on the surface properties of the polyglutamates. Water contact angle and water absorption data show that the hydrophilicity of these polyglutamate surfaces decreases with the increasing of methylene in the alkyl group. Protein adsorption on these polyglutamate surfaces increases with the enhancing of surface hydrophobicity. However, the changes in platelets adhesion could be attributed to the hydrophilicity/hydrophobicity of the polyglutamates and the specific effect of alkyl group. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2011

Fibrous membranes (nonwoven meshes) prepared via electrospinning technique have great potential in tissue engineering. This work is the first study on the behaviors of blood platelets at the nanostructured surface generated by electrospinning. Poly[acrylonitrile-co-(N-vinyl-2-pyrrolidone)] (PANCNVP) that shows excellent antiplatelet adhesion ability was directly electrospun onto its dense membrane surface. Polyacrylonitrile (PAN) samples were used as controls. The depth as well as the density of the nanofibers can be easily controlled. The results showed that the PANCNVP dense membrane certainly suppressed the activation and adhesion of platelets. However, whether the nanofibers and underlying membranes were composed of PAN or PANCNVP, the nanostructured surfaces promoted the activation, adhesion, and orientation of platelets. It was also found that, if the space between fibers was too large or the depth of fibers was too small, the nanostructured surface did not change the property of antiplatelet adhesion of PANCNVP. The promotion of activation and adhesion of platelets was obviously due to the presence of nanofibers, which induced the changes of surface topography and charge. © 2008 Wiley Periodicals, Inc. J Biomed Mater Res, 2009

We describe the synthesis of three novel thermoresponsive copolymers of acrylonitrile (AN) with N-isopropylacrylamide (NIPAM) by a combination of reversible addition-fragmentation chain transfer (RAFT) polymerization and atom transfer radical polymerization (ATRP). Linear copolymer polyacrylonitrile (PAN)-b-PNIPAM was directly prepared by RAFT polymerization. Comb-like copolymers were synthesized by ATRP using brominated AN/2-hydroxyethyl methacrylate copolymers as macroinitiators, which were prepared by RAFT polymerization. FT-IR, NMR, and GPC were employed to characterize the synthesized copolymers. Results indicate that the polymerization processes can be well controlled and the resultant copolymers have well-defined structures as well as narrow polydispersity. Then dense films were fabricated from these thermoresponsive copolymers and the surface wettability was evaluated by water contact angle measurements at different temperatures. It is found that the surface wettability is temperature-dependant and both the transition temperature and decrement of water contact angle are affected by the copolymer shapes as well as the length of PNIPAM blocks. Considering the excellent fiber- and membrane-forming properties of PAN-based copolymers, the obtained thermoresponsive copolymers are latent materials for functional fibers and membranes. © 2008 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 47: 92–102, 2009