Recent years have witnessed great developments in biobased polymer packaging films for the serious environmental problems caused by the petroleum-based nonbiodegradable packaging materials. Chitosan is one of the most abundant biopolymers after cellulose. Chitosan-based materials have been widely applied in various fields for their biological and physical properties of biocompatibility, biodegradability, antimicrobial ability, and easy film forming ability. Different chitosan-based films have been fabricated and applied in the field of food packaging. Most of the review papers related to chitosan-based films are focusing on antibacterial food packaging films. Along with the advances in the nanotechnology and polymer science, numerous strategies, for instance direct casting, coating, dipping, layer-by-layer assembly, and extrusion, have been employed to prepare chitosan-based films with multiple functionalities. The emerging food packaging applications of chitosan-based films as antibacterial films, barrier films, and sensing films have achieved great developments. This article comprehensively reviews recent advances in the preparation and application of engineered chitosan-based films in food packaging fields.

Polystyrene nanofibres were electrospun with the inclusion of cationic surfactants ， dodecyltrimethylammonium bromide (DTAB) or tetrabutylammonium chloride (TBAC), in the polymer solution. A small amount of cationic surfactant effectively stopped the formation of beaded fibres during the electrospinning. The cationic surfactants were also found to improve the solution conductivity, but had no effect on the viscosity. Only DTAB had an effect on the surface tension of the polymer solution, the surface tension decreasing slightly with an increase in the concentration of DTAB. The formation of beaded fibres was attributed to an insufficient stretch of the filaments during the whipping of jet, due to a low charge density. Adding the cationic surfactants improved the net charge density that enhanced the whipping instability. The jet was stretched under stronger charge repulsion and at a higher speed, resulting in an exhaustion of the bead structure. In addition, a polymer/surfactant interaction was found in the

Fabrics having an interesting unidirectional water-transfer effect have been prepared by a special coating technique to create a wettability gradient across the fabric thickness, and the treated fabrics also show considerably different breakthrough pressures on the two fabric sides.

Superhydrophilic and superoleophobic materials are very attractive for efficient and cost-effective oil-water separation, but also very challenging to prepare. Reported herein is a new superamphiphobic coating that turns superhydrophilic and superoleophobic upon ammonia exposure. The coating is prepared from a mixture of silica nanoparticles and heptadecafluorononanoic acid-modified TiO2 sol by a facile dip-coating method. Commonly used materials, including polyester fabric and polyurethane sponge, modified with this coating show unusual capabilities for controllable filtration of an oil-water mixture and selective removal of water from bulk oil. We anticipate that this novel coating may lead to the development of advanced oil-water separation techniques.

tails of this procedure have been published previously [18]. An aqueous solution of PBDT has a LC nature above 2.8 wt.-% (C * LC ). DMA-PAA-Q (Kohjin Co. Ltd.) was used as the monomer without further purification. MBAA (Junsei Chemical Co. Ltd.) was recrystallized with ethanol and used as a crosslinker. Acrylamide (AAm) (Junsei Chemical Co. Ltd.) was recrystallized with chloroform and used as the neutral monomer. Potassium persulfate (KPS) (Wako Pure Chemical Industries Ltd.) was recrystallized with water and used as the initiator. Water was deionized and purified with 0.22 lm and 5 lm membrane filters before use. 2 wt.-% PBDT, 2 mol L -1 DMAPAA-Q (or AAm), 0.5, 1, or 2 mol-% (to DMAPAA-Q) MBAA, and 0.1 mol-% KPS were dissolved in water. These solutions were poured into reaction cells consisting of a pair of glass plates with a 2 mm spacing. Radical polymerization was performed at 60°C. After gelation, the products were immersed in a large amount of water and allowed to reach an equilibrium state for a week.Measurements: The swelling degree of the gels, Q, is defined here as the weight ratio of a swollen to a dried gel [23]. The dried gels were obtained by keeping them in a desiccator for 12 h and in a vacuum oven at 60°C for 6 h.Optical-microscopy observation was performed using a crossed polarizing microscope (Olympus, BH-2) at room temperature. Sample gels were placed on glass plates and the upper free surfaces were observed. Birefringence, Dn, was measured by a crossed polarizing microscope with a Berek compensator [20]. In the measurement, many microscopic domains randomly oriented in the bulk were observed. Thus, we chose one of large domains and selected the orientation direction by turning the sample under the crossed polarizing microscope. Under these conditions, Dn was measured from the retardation. Average Dn was determined by measuring Dn several times for each sample.

No abstract

Wormlike micelles, obtained firstly in anionic surfactant sodium dodecyl trioxyethylene sulfate (SDES) solutions in the presence of AlCl3, were studied using zero-shear viscosities and freeze-fracture TEM micrographs. Then the effects of inorganic salts with different cations, AlCl3, MgCl2, CaCl2, and NaCl, on the rheological properties and microstructures of the SDES micellar solutions were investigated generally. The steady-shear viscosity followed the Cross empirical equation, and the dynamic vlscoelasticity was well modeled by the simple Maxwell model. There exists an optimal molar ratio R m of surfactant to salt at which the micelles reach maximum growth. We find R m ≤ 1/5 for SDES/NaCl system, and R m ≈ 1/3 for the other three systems. Variations in the surfactant packing parameter R p help explain the changes of rheology and microstructure of the solutions, according to the cationic radii and charges and the interaction between the cations and surfactant molecular headgroups. The ability of cations that make the micelles reach a maximum growth followed the order of Al3+ > Mg2+ > Ca2+ > Na+.

A POSS-PMMA copolymer has been synthesised by conventional free-radical polymerisation reaction. Uniform electrospun fibres from this copolymer showed a water contact angle as high as 165 degrees with a sliding angle as low as 6 degrees . For the first time, we found that the electrospun fibres had a bundled nanofibril secondary structure with an ordered POSS morphology on the fibre surface.