A novel family of multi-responsive, tough, and reversible hydrogels were prepared by the combination of dipole-dipole interaction, hydrogen bonding interaction and slightly chemical cross-linking, using monomers of acrylonitrile, sodium allylsulfonate and itaconic acid. Reversible gel-sol transition was achieved by the flexible conversion of the dipole-dipole interactions between acrylonitrile-acrylonitrile and acrylonitrile-sodium thiocyanate, and the hydrogels could freely form desired shapes. The dipole dipole and hydrogen bonding interactions improved the mechanical strength of the hydrogels with a compressive stress of 2.38 MPa. Meanwhile, the hydrogels sustained cyclic compressive tests with 60% strain, and exhibited excellent elastic property. The hydrogels were sensitive to pH and ionic strength, and could keep their perfect spherical structures without any obvious cracks even after immersing in strong ionic strength (or pH) solution for several reversible cycles. Furthermore, the hydrogels were recycled for environmental pollution remediation, and showed great potential to be applied in water treatments and other related fields.

In this study, heparin-mimicking hydrogel thin films are covalently attached onto poly(ether sulfone) membrane surfaces to improve anticoagulant property. The hydrogel films display honeycomb-like porous structure with well controlled thickness and show long-term stability. After immobilizing the hydrogel films, the membranes show excellent anticoagulant property confirmed by the activated partial thromboplastin time values exceeding 600 s. Meanwhile, the thrombin time values increase from 20 to 61 s as the sodium allysulfonate proportions increase from 0 to 80 mol%. In vitro investigations of protein adsorption and blood-related complement activation also confirm that the membranes exhibit super-anticoagulant property. Furthermore, gentamycin sulfate is loaded into the hydrogel films, and the released drug shows significant inhibition toward E. coli bacteria. It is believed that the surface attached heparin-mimicking hydrogel thin films may show high potential for the applications in various biological fields, such as blood contacting materials and drug loading materials.

A recyclable and regenerable magnetic polysaccharide absorbent for methylene blue (MB) removal was prepared by coating magnetic polyethyleneimine nanoparticles (PEI@MNPs) with sulfonated chitosan (SCS) and further cross -linked with glutaraldehyde. The driving force for coating is the electrostactic interaction between positively charged PEI and negatively charged SCS. Infrared spectra, zeta potential, thermal gravimetric analysis and X-ray diffraction demonstrated the successful synthesis of magnetic polysaccharide absorbent. The self-assembly of polysaccharide with magnetic nanopartices did not alter the saturation magnetization value of the absorbent confirmed by vibrating sample magnetometer. The nanoparticles showed fast removal (about 30 min reached equilibrium) of MB. In particular, the removal ability of MB after desorption did not reduce, demonstrating an excellent regeneration ability. Our study provides new insights into utilizing polysaccharides for environmental remediation and creating advanced magnetic materials for various promising applications.

In this study, a robust and straightforward method to covalently attach multi-functional hydrogel thin layers onto substrates was provided. In our strategy, double bonds were firstly introduced onto substrates to provide anchoring points for hydrogel layers, and then hydrogel thin layers were prepared via surface cross-linking copolymerization of the immobilized double bonds with functional monomers. Sulfobetaine methacrylate (SBMA), sodium allysulfonate (SAS), and methyl acryloyloxygen ethyl trimethyl ammonium chloride (METAC) were selected as functional monomers to form hydrogel layers onto polyether sulfone (PES) membrane surfaces, respectively. The thickness of the formed hydrogel layers could be controlled, and the layers showed excellent long-term stability. The PSBMA hydrogel layer exhibited superior antifouling property demonstrated by undetectable protein adsorption and excellent bacteria resistant property; after attaching PSAS hydrogel layer, the membrane showed incoagulable surface property when contacting with blood confirmed by the activated partial thromboplastin time (APTT) value exceeding 600 s; while, the PMETAC hydrogel thin layer could effectively kill attached bacteria. The proposed method provides a new platform to directly modify material surfaces with desired properties, and thus has great potential to be widely used in designing materials for blood purification, drug delivery, wound dressing, and intelligent biosensors.

Hollow fiber membranes with satisfied blood compatibility and antibacterial property are desired in blood purification. Herein, a series of heparin-like copolymers of poly(methyl methacrylate-vinyl pyrrolidone -sodium styrene sulfonate-sodium acrylate) (poly(MMA-VP-SSNa-SA)) were synthesized by free radical solution polymerization. The mixture was directly blended with polyethersulfone (PES) solution to prepare hollow fiber membranes. The membranes were characterized by Fourier transform infrared spectroscopy (FTIR) and scanning electron microscopy (SEM). Blood compatibility of the hollow fiber membranes was evaluated via protein adsorption, platelet adhesion, clotting time, and hemolysis assay. Besides, Ag nanoparticles were immobilized onto the hollow fiber membranes efficiently by a simple and green method, and the antibacterial property and blood compatibility of the Ag-loaded membranes were then investigated. The results indicated that the approach towards blood compatible and antibacterial hollow fiber membrane is efficient and flexible for the modification for membrane materials.

Graphene oxide (GO), a graphene nanomaterial with great application potential, possesses promising adsorption abilities towards various water contaminants due to the ultra-large surface area and the nature of electric charge on the surface. However, ultrahigh centrifugation for a prolonged time is strongly needed to collect the highly dispersed GO in the recovery process. In this study, a GO-based polymeric composite particle with core-shell structure was fabricated by a facile method. Polyethersulfone (PES) was chosen as the shell to enwrap GO through a liquid-liquid phase inversion process, since the PES shell presented high porosity, good mechanical property and easily modified ability. Methylene blue (MB), a cationic dye, was chosen as the adsorbate to investigate the adsorption capabilities, kinetics and isotherms of the prepared particles. The PES@GO core-shell particles displayed an adsorption capacity as high as 352.11 mg g(-1) for MB dye, and the adsorption rates could be improved by modifying the PES shells with hydrophilic fillers. The MB adsorption behavior fitted the pseudo-second- order kinetic model and the Langmuir isotherm very well, and the adsorption process was controlled by the intra-particle diffusion. In addition, a particle column was used to further study the removal ability of environmental toxins, and the results revealed that the composite particles had great potential to remove cationic dyes for wastewater treatment on an industrial scale.

In this study, poly(sodium p-styrenesulfonate)/poly(methyl methacrylate) particles were facilely prepared by in situ cross-linked polymerization followed with a liquid-liquid phase inversion technique. The particles exhibited selective adsorption for cationic dyes due to the negatively charged sulfonic groups. The intra-particle diffusion process was the rate-limiting step for the adsorption of methylene blue. More than 90% of cationic dye was removed by the adsorption column of the particles after three circulations. The particles could be facilely fabricated and industrially used for wastewater treatment.

A universal mold casting approach for the preparation of cation-exchange membranes (CEMs) and anion-exchange membranes (AEMs) with ultrahigh ion-exchange capacities (IECs) is developed based on in situ cross-linking polymerization of acrylic acid (AA) and 2-vinylpyridine (2VP), respectively. This new method produced ultrahigh IECs of 7.88 mequiv g(-1) for CEM and 6.27 mequiv g(-1) for AEM, which are 8.8 and 7.0 times that (0.89 mequiv g(-1)) of Nafion 117, respectively. Also, the prepared membranes demonstrate excellent thermal and chemical stability and acceptable conductivity. As a consequence, the membranes show relatively high performance for ion-exchange application and methanol barrier, exhibiting ion permeabilities of 2.06 x 10(-7) cm(2) s(-1) for Na+, 2.57 x 10(-7) cm(2) s(-1) for Ca2+, 1.45 x 10(-7) cm(2) s(-1) for Cu2+ regarding CEMs, and 7.72 x 10(-7) cm(2) s(-1) for methanol regarding AEMs. These results indicate that the CEMs and AEMs fabricated from the universal mold casting approach are promising candidates for targeting ultrahigh ion-exchange capacity membranes.

The chemical compositions are very important for designing blood-contacting membranes with good antifouling property and blood compatibility. In this study, we propose a method combining ATRP and click chemistry to introduce zwitterionic polymer of poly(sulfobetaine methacrylate) (PSBMA), negatively charged polymers of poly(sodium methacrylate) (PNaMAA) and/or poly(sodium p-styrene sulfonate) (PNaSS), to improve the antifouling property and blood compatibility of polysulfone (PSf) membranes. Attenuated total reflectance-Fourier transform infrared spectra, X-ray photoelectron spectroscopy and water contact angle results confirmed the successful grafting of the functional polymers. The antifouling property and blood compatibility of the modified membranes were systematically investigated. The zwitterionic polymer (PSBMA) grafted membranes showed good resistance to protein adsorption and bacterial adhesion; the negatively charged polymer (PNaSS or PNaMAA) grafted membranes showed improved blood compatibility, especially the anticoagulant property. Moreover, the PSBMA/PNaMAA modified membrane showed both antifouling property and anticoagulant property, and exhibited a synergistic effect in inhibiting blood coagulation. The functionalization of membrane surfaces by a combination of ATRP and click chemistry is demonstrated as an effective route to improve the antifouling property and blood compatibility of membranes in blood-contact.