Yingshan Zhou

Preparation and characterization of novel hydrophobic cellulose fabrics with polyvinylsilsesquioxane functional coatings

A series of novel hydrophobic cotton fabrics with polyvinylsilsesquioxane (PVS) polymer functional coatings were successfully prepared by solution immersion. The influence of the added amount of PVS polymer on the morphology, resistance to thermal and thermooxidative degradation, and hydrophobic properties of the treated cotton fabrics was studied by attenuated total reflection infrared spectroscopy, scanning electron microscopy, thermogravimetric analysis, and water contact angle measurements, respectively. The experimental results show that the PVS polymer formed a protective film on the surface of the cotton fibers; the resistance to thermal and thermooxidative degradation, and the water-repellent properties of the novel cotton fabrics were also improved with increasing added amount of PVS polymer, compared with that of reference material. The enhancement in the thermal properties of the treated cotton fabrics can likely be attributed to synergistic carbonization between the PVS protective layer and the cellulose fibers during thermal degradation. Meanwhile, it was also found that, with increasing added amount of PVS polymer, the hydrophobicity of the treated cotton fabrics was greatly improved. The noticeable improvement in the hydrophobicity of the treated cotton fabrics is ascribed to the combination of low-surface-energy PVS film and the intrinsically rough surface of the woven cotton fabrics. This strategy for fabricating novel cellulose fabrics provides a guide for the development of high-performance functional cellulose fabrics with tunable properties in the textile industry.

Fabrication of hydrophobic cotton fabrics inspired by polyphenol chemistry

Highly hydrophobic cotton fabrics were fabricated via coordination assembly of tannic acid (TA) and Fe(III) followed by treatment with 1-octadecylamine. Scanning electron microscopy analysis showed that this novel Fe(III)/TA metalorganic system coated the cotton fabrics and affected the surface roughness, making the textiles hydrophobic. This approach is facile and low cost without substrate limitation or addition of fluorinated chemicals. Wettability tests showed that the highly hydrophobic textiles were robustly resistant to acid, alkaline, and salt corrosion and long-term laundering. In addition, the obtained highly hydrophobic surface could effectively separate oil–water mixtures by simple filtration. The simplicity and versatility of this direct approach inspired by polyphenol chemistry may facilitate fast development of functional textiles for many applications.

Preparation and characterization of monodisperse solvent-free silica nanofluids

ABSTRACT A series of solvent-free ionic silica (SiO2) nanofluids of 12.3–17.3 nm in diameter were synthesized by surface functionalizing nanoscale SiO2 with a charged corona and ionically tethering with oligomeric chains as canopy. The structure and properties of the nanofluids were systematically characterized by Fourier transform infrared (FTIR), differential scanning calorimeter (DSC), transmission electron microscopy (TEM), thermogravimetric analysis (TGA), and rheology tests. The resultant nanofluids with low-molecular-weight oligomeric as canopy are homogeneous, stable yellow-like fluids with no evidence of phase separation at room temperature, while other nanofluids containing high-molecular-weight as canopy behave like a soft glassy, and they exhibit fluidity with still high modulus and viscosity above 60°C. For deeper understanding of the nature of SiO2 nanofluids, the rheological behavior, thermal stability, as well as morphology of SiO2 nanofluids were investigated in details. The flow properties of nanofluids could be easily regulated from soft glassy to free flowing liquids by varying the molecule weight of canopy. Most importantly, the thermal stability, rheological behavior, as well as morphology can be also regulated through varying molecule weight and thickness of canopy, which will guide our future work on synthesis of nanofluids with controllable physical properties. GRAPHICAL ABSTRACT

Functionalized magnesium hydroxide fluids/acrylate-coated hybrid cotton fabric with enhanced mechanical, flame retardant and shape-memory properties

AbstractFunctionalized magnesium hydroxide fluids (MHFs) with both grafting reactive acrylate groups and organic long chain ion are successfully fabricated and then incorporated in poly(ethylene glycol) diacrylate (PEGDA) to produce flexible MHFs/PPEGDA coated hybrid cotton fabric via UV photo-polymerization. The morphology, composition, transparency, rheological behavior, mechanical and flamexa0retardantxa0properties of MHFs/PPEGDA coating are systematically characterized by various techniques. It is found that tensile strength and young’s modulus of MHFs/PPEGDA/cotton composite are as high as 46 and 556xa0MPa at MHFs loading amount of 40xa0wt%, respectively, an enhancement of 58.6 and 66.4% in comparison with PPEGDA/cotton composite. What’s more, the addition of MHFs not only reduces the surface energy of PEGDA to improve its film-forming property during polymerization process, but also maintains high transparency over 90%. Besides the above mentioned advantages, MHFs/PPEGDA coating as thermal induced shape memory material could be fixed their shape at −xa04xa0°C and rapidly recover their original shape at 60xa0°C, which is related to the melting transition temperature of MHFs. More importantly, with the synergistic effect of magnesium hydroxide and surface grafted organic long chain ion molecules, the flamexa0retardantxa0property of MHFs/PPEGDA/cotton is also significantly improved. These functionalized organic/inorganic fluids provide a simple approach to fabricate high performance cellulose fabrics with tunable properties in the textile industry.n

Photocrosslinked methacrylated chitosan-based nanofibrous scaffolds as potential skin substitute

AbstractNanofibers based on natural polymers have recently been attracting research interest as promising materials for use as skin substitutes. Here, we prepared photocrosslinked nanofibrous scaffolds based on methacrylated chitosan (MACS) by photocrosslinking electrospun methacrylated chitosan/poly (vinyl alcohol) (PVA) mats and subsequently removing PVA from the nanofibers. We comprehensively investigated the solution properties of MACS/PVA precursors, the intermolecular action between MACS and PVA components, and the morphology of MACS/PVA nanofibers. Results indicated that the fiber diameter and morphology of the photocrosslinked methacrylated chitosan-based nanofibrous scaffolds were controlled by the MACS/PVA mass ratio and showed highly micro-porous structures with many fibrils. In vitro cytotoxicity evaluation and cell culture experiments confirmed that MACS-based mats with micro-pore structure were biocompatible with L929 cells and facilitated cellular migration into the 3D matrix, demonstrating their potential application as skin replacements for wound repair.n

A facile and green approach to prepare monodispersion nanonickel nanofluids

ABSTRACT This paper first develops a novel approach to prepare solvent-free nanonickel (Ni) nanofluids via hydrogen bonding between poly(ethylene oxide)-block-poly(propylene oxide)-block-poly(ethylene oxide) and 3-(Trimethoxysilyl)-1-propanethiol-modified Ni powder with average diameter of 80u2009nm to solve the problem of nanoparticles agglomerating due to the anisotropic dipolar attraction. It is interestingly found that Ni nanofluid is solid at room temperature while it undergoes solid–liquid transition without solvent at 50.7°C. The content of Ni is up to 12.1u2009wt%. The average diameter of core-shell structure of Ni nanofluids is 182u2009nm without agglomerations. It is worth noting that incorporation of Ni powder can elevate remarkably initial decomposition temperature of block copolymer due to high dispersity of Ni powder after modification. In addition, the viscosity of Ni nanofluids is found to be less than 10u2009Pau2009·u2009s at 100°C, which is between that of water and honey, 0.001 and 10u2009Pau2009·u2009s, respectively, at 20°C. More importantly, the Ni nanofluids exhibit excellent dispersion in water and other organic solvents for 2 months due to amphiphilic properties of the modifier molecule. These unique properties of Ni nanofluids may offer new scientific and technical opportunities for application of Ni powder in the form of liquid-like status.

UV-blocking, superhydrophobic and robust cotton fabrics fabricated using polyvinylsilsesquioxane and nano-TiO 2

UV-blocking, superhydrophobic and robust cotton fabrics were successfully developed by combination of polyvinylsilsesquioxane (PVS) and nano-TiO2 for the first time. The influence of the add-on amount on morphologies, ultraviolet (UV) protection, hydrophobicity, mechanical properties, rigidity and thermal degradation of the treated cotton fabrics was studied. The nano-TiO2 particles were found to be embedded in the PVS film layer on the surface of cotton fibers by covalent Ti–O–Si bonds after curing. The UV blocking and hydrophobic properties of the functionalized cotton fabrics were also improved with increases in the amount of add-on, compared to the reference materials. The improvements on the UV blocking, water repellency and rigidity of the treated cotton fabrics are likely attributed to synergism between the PVS polymer and nano-TiO2. The mechanical properties of the finished cotton fabrics are significantly enhanced by treatment of composite coatings. However, the resistance to thermal degradation evidently did not change despite changes in the add-on amount. Hence this strategy for developing the composite coatings can guide in constructing the advanced functional surface, and the discovery of this new class of UV-blocking, superhydrophobic and robust cotton fabrics has many potential applications such as advanced UV-blocking textiles, stretchable electronic devices and self-cleaning fields.

Fabrication of superhydrophobic and superoleophilic polybenzoxazine-based cotton fabric for oil–water separation

Superhydrophobic material involves the fabrication of appropriate roughness and low surface energy. Studies concerning enhancing the attachment between substrates and low surface energy material have been reported. Hence, it might also be feasible to make low surface energy material as an interface binder to enhance the attachment. In our work, the simple dip-coating method was used to fabricate polybenzoxazine (PBZ)/SiO2-coating cotton (PBZSC) fabric for rapid oil–water separation. The surface morphology and wettability of the PBZSC fabric as well as the properties of the separation were explored using various methods. These results demonstrated that PBZSC fabric not only had excellent thermal properties, but also maintained excellent superhydrophobicity (WCAu2009>u2009150°) under various harsh conditions which was mainly attributed to higher surface roughness contributed by SiO2 and lower surface energy, heat resistance as well as acid and alkali resistance from PBZ resin, respectively. More importantly, the separation conducted by the PBZSC fabric not only showed great recycle property, but also separated a series of oil and water mixtures with up to 96% separation efficiency. Therefore, it is anticipated that this low-cost PBZSC fabric will be readily and widely utilized in designing multifunctional membrane for large-area oil-spill cleanup without using fluoropolymers or silicones.Graphical abstract