A nanocomposite (NC) hydrogel crosslinked by inorganic Laponite XLG was successfully synthesized via in situ free radical polymerization of monomers N,N-diethylacrylamide and (2-dimethylamino) ethyl methacrylate (DMAEMA). Polymerization was carried out at room temperature due to the accelerating effect of DMAEMA. The as-prepared hydrogels displayed controlled transformation in optical transmittance and volume in response to small diversification of environmental factors, such as temperature and pH. The compressive strength of swollen D 6:1 G 6 hydrogels was as high as 2219 kPa while compressive strain was 95%. Cyclic compression measurement exhibited good elastic properties of NC hydrogels. This work provides a facile method for fabricating stimuli-responsive hydrogels with superior mechanical property.

In this work, we evaluated the effect of crosslinking concentration on the affinity of poly (2-acrylamido-2-methyl-1-propansulfonic acid) (PAMPS) hydrogel-supported Fe 3 O 4 nanozyme towards substrates (tetramethylbenzidine (TMB) and H 2 O 2 ). The peroxidase-like catalytic activity of PAMPS/Fe 3 O 4 nanozyme was discussed with respect to crosslinking concentration of PAMPS hydrogel for the oxidation of TMB in the presence of H 2 O 2 at room temperature. High catalytic activity was achieved due to good dispersion of Fe 3 O 4 nanozyme in the hydrogel network and strong affinity of PAMPS hydrogel-supported Fe 3 O 4 nanozyme towards substrates. The affinity between the hydrogel-supported Fe 3 O 4 nanozyme and substrates can be improved by regulating the crosslinking concentration of PAMPS hydrogel without other trenchant experimental conditions. In addition, the result indicated that H 2 O 2 can be detected even at a concentration as low as 1. 5 3

The layer-by-layer (LBL) assembly technique is an attractive method to make functional multilayer thin films and has been applied to fabricate a wide range of materials. LBL materials could improve optical transmittance and mechanical properties if the film components were covalently bonded. Covalently bonded nanocomposite multilayer films were prepared by employing hydrophilic aliphatic polyisocyanate (HAPI) as the reactive component, to react with Laponite and polyvinyl alcohol (PVA). FT-IR spectra suggested that HAPI reacted with Laponite and PVA at ambient temperature rapidly. Ellipsometry measurement showed that the film thickness was in linear growth. The influences of HAPI on the optical, mechanical and thermal properties of the films were investigated by UV-Vis spectroscopy, tensile stress measurement, DSC and TGA. The obtained results showed that the optical transmittance and mechanical strength were enhanced when the film components were covalently bonded by HAPI. V C 2015 Wiley Periodicals, Inc. J. Polym. Sci., Part B: Polym. Phys. 2015, 00, 000-000 KEYWORDS: covalently bonded; layer-by-layer; nanocomposites; self-assembly; thin films INTRODUCTION The layer-by-layer (LBL) assembly technique is an attractive method to make functional multilayer thin films and has been applied in the fabrication of nanodevice, drug release, and biomimetic materials.1-4 LBL multilayer films are more versatile in many aspects than bulk materials because they have more precisely controlled composition and structure at nanoscale dimensions. 5 Many researchers have investigated freestanding LBL films.6-8 However, the LBL ultrathin film breaks or decomposes easily during the application, which is one of the main shortages that hampers the application of the materials.9 Covalent assembly is an effective strategy for improving the physical or chemical properties of the LBL films.10-12 Another approach is achieved by introducing inorganic materials such as Laponite, montmorillonite and carbon nanotube into the LBL multilayer films. [13][14][15][16] Researchers have employed hydrogen bond, dipolar bond, or electrostatic attraction between polymer and inorganic particles to fabricate nanocomposite LBL multilayer films. 17,18 This type of physical interaction, however, often leads to unstable multilayer films in strong acid, strong alkali or high humidity conditions.

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A robust and coarse surface mesh was fabricated by introducing a hydrogel coating with interpenetrating polymer network (IPN) structure on stainless steel mesh. The IPN hydrogel was prepared by crosslinking polymerization of acrylic acid (AA) followed by condensation reaction of polyvinyl alcohol (PVA) and glutaraldehyde (GA) at room temperature. As a result, the roughness of modified mesh was enhanced obviously and oil droplet underwater showed a larger contact angle. The hydrogel-coated surface showed an underwater superoleophobicity with an oil contact angle of 153.92 6 1.08. Besides, stable wettability was observed. The mesh can selectively separate oil from water with a high separation efficiency of above 99.8%. This work provides a facile method to strengthen the coating and enhance the efficiency of oil-water separation.