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Many advanced wound healing dressings exist, but there is little high-quality evidence to support them. To determine the performance of a novel amorphous hydrogel (EHO-85) in relation to its application, we compared its rheological properties with those of other standard hydrogels (SH), and we assessed the induction of acceleration of the early stages of wound healing as a secondary objective of a prospective, multicenter, randomized, observer-blinded, controlled trial. The patients were recruited if they had pressure, venous, or diabetic foot ulcers and were treated with EHO-85 (n = 103) or VariHesive® (SH) (n = 92), and their response was assessed by intention-to-treat as wound area reduction (WAR (%)) and healing rate (HR mm2/day) in the second and fourth weeks of treatment. Results: EHO-85 had the highest shear thinning and G′/G″ ratio, the lowest viscous modulus, G″, and relatively low cohesive energy; EHO-85 had a significantly superior effect over SH in WAR and HR, accelerating wound healing in the second and fourth weeks of application (p: 0.002). This superiority is likely based on its optimal moisturizing capacity and excellent pH-lowering and antioxidant properties. In addition, the distinct shear thinning of EHO-85 facilitates spreading by gentle hand pressure, making it easier to apply to wounds. These rheological properties contribute to its improved performance. [ABSTRACT FROM AUTHOR]

The effect of itaconic acid (IA) as functionalizing agent on the static mechanical properties (Young's modulus, tensile stress, ultimate properties, and hardness) of core/shell polymers made of styrene and butyl acrylate by a two-stage microemulsion polymerization process is reported. High-polymer content (>35 wt%) was obtained in the first stage (seed) by adding more monomer semicontinuously to the parent microemulsion-latex; however, the characteristics of microemulsion-made latexes were preserved, that is, nanometer particles (2 x [10.sup.6] g/mol). The IA content in the shell was varied from 0 to 20 wt% with respect to that of the polymer in the shell, either polystyrene or poly(butyl acrylate) (PBA). High conversions in both stages (>84 %), final core-shell latex with relatively high-polymer content (ca. 20 wt%), and particle with diameters smaller than 78 nm were obtained. The fact that particle size grew from the first (ca. 50 nm) to the second stages (ca. 75 nm) and that the polymers showed two glass transitions suggests that a core shell structure was obtained. The presence of the functionalizing agent (IA) modified the mechanical properties, especially when PBA was in the shell. POLYM. ENG. SCI., 53: 1529-1535, 2013. © 2012 Society of Plastics Engineers, INTRODUCTION Core/shell polymers are typically made of a polymer with a lower glass transition temperature ([T.sub.g]) and another with a higher [T.sub.g] than the temperature at which the material will [...]

In textile printing, hydrotropic components are usually added to print paste formulations promoting the hydration of textile fabrics by disrupting the hydrogen bonding network between water molecules. For this purpose, urea is commonly used but nevertheless, its presence causes water eutrophication and their reduction or replacement by more environmentally-friendly products is required. In the present work, we have studied an alternative hydrotropic product (polyethylene glycol, PEG) to replace urea. A factorial design of experiments has been carried out to identify the factors that optimize several variables of interest such as viscosity of the printing paste and fabric colour strength. The results showed that a reduction of 70 wt% of urea was achieved by using PEG 400, while preserving the performance of printing formulation. The viscosity of these eco-friendly printing paste formulations was similar to that of the original urea-based formulations and, more interestingly, fabrics showed similar colour strength and fastness to those of fabrics printed by the conventional method. [ABSTRACT FROM AUTHOR]

Nano-emulsion formation by the phase inversion temperature (PIT) method is reviewed. Characteristic features of low-energy emulsification are first summarized, and then, follows a description of the main characteristics of the PIT emulsification method. The main focus is on the relation between phase behavior and nano-emulsion formation. Emphasis is put on the key role of phase transitions involving equilibrium phases such as lamellar liquid crystalline and/or bicontinuous microemulsion phases to obtain nano-emulsions with minimum and controlled droplet size. [ABSTRACT FROM AUTHOR]

Cosmeto-textiles, which allow the administration of molecules when in contact with the skin, are increasingly being developed by cosmetic industries. We have designed an innovative approach for cosmeto-textile products, based on the impregnation of textile fibers with chitosan hydrogels, which have been cross-linked with genipin and loaded with dihydroxyacetone, which is an active component that induces sunless tanning. Dihydroxyacetone-loaded chitosan hydrogels have been prepared and characterized by means of cryogenic scanning electron microscopy (cryo-SEM). The images showed that genipin cross-linking decreases the mesh distance of hydrogels. The release of dihydroxyacetone from these cross-linked genipin chitosan hydrogels has been studied by a dialysis membrane method. These dihydroxyacetone-loaded chitosan hydrogels have been incorporated to polyamide textiles by a simple padding technique. The presence of dihydroxyacetone on these textiles has been detected by hyperspectral imaging on a dark field high resolution optical microscope. Finally, the performance of fabrics as cosmeto-textiles, with a tanning effect, has been evaluated by skin-colorimetry measured with an evaluation panel of 10 people. The results have demonstrated that dihydroxyacetone-loaded textiles produce a tanning effect on skin, and incorporation of dihydroxyacetone-loaded chitosan hydrogels into polyamide fabrics represents a friendly and appropriate strategy to obtain a cosmeto-textile with tanning effect. [ABSTRACT FROM AUTHOR]

Nano‐emulsion formation by the phase inversion composition method is reviewed. The relationship between phase behavior and nano‐emulsion formation is revised with emphasis on the key role of phase transitions involving changes in the sign of the curvature of the surfactant layer (inversion) via zero‐average‐curvature structures such as bicontinuous microemulsions or lamellar liquid crystalline phases. The different low‐energy methods that can be involved in a nano‐emulsification process at constant temperature are also discussed. [ABSTRACT FROM AUTHOR]

A new nanocarrier for loading and releasing drugs is reported, and ketoprofen was used as a model drug. More precisely, the carrier is a hybrid material prepared by combining oil-in-water (O/W) nanoemulsions, into which the drug has been solubilized, with mesostructured silica. This organic-inorganic hybrid material shows a controlled release of the drug that is pH dependent. If the drug is impregnated into the bare hierarchical meso-/macroporous dual silica material, obtained after the removal of the organic components by extraction, only 8 wt.-% of ketoprofen is released in a phosphate buffer medium (pH 7.4), probably owing to its low solubility in the aqueous phase. The drug solubility and release are increased strongly by the addition of Pluronic micelles to the receptor phase; this suggests a micelle-promoted and -assisted release mechanism. Whatever the vehicle, the release profiles of ketoprofen always follow the Korsmeyer-Peppas model with a diffusional release exponent value lower than 0.5, characteristic of a pseudo-Fickian release mechanism. Moreover, the release of ketoprofen is better controlled from the hybrid nanocarrier than from the hierarchical bare porous silica. [ABSTRACT FROM AUTHOR]

A series of hafnia-silica mixed oxides of HfO2(SiO2)8 stoichiometry were prepared by a sol-gel method followed by freeze-drying. Two hafnium precursors, Hf(OiPr)4 and Hf(OtBu)4 were examined under a variety of aqueous-alcoholic systems. A decisive dependence of the alcoholic solvent on the gel formation and the surface and porosity of the final materials was found, which in turn were key to the enhancement of catalysis. Hence, acid hydrolysis and gelification of Hf(OiPr)4 in tert-butyl alcohol, followed by lyophilization, yielded a material with the highest mesoporosity and specific surface area. This catalyst behaved most efficiently in the acid-catalyzed cyclization of citronellal to isopulegol at room temperature. Furthermore, this cryogel also presented combined Lewis acidity and hydrogen bonding that resulted in higher diastereoselectivity for the above reaction. These results highlight the effect of how the textural and, therefore catalytic, properties of the cryogels depend decisively on the solvents chosen for their synthesis. [ABSTRACT FROM AUTHOR]

ABSTRACT Hyaluronic acid (HA) is a natural polysaccharide that is widely distributed in the human body. Its physicochemical properties and high biocompatibility make it a good candidate for biomedical and pharmaceutical uses. In the present work, we report HA-based hydrogels that could be applied as drug delivery systems or as implants for the treatment of joint diseases. We use butanediol diglycidyl ether as a chemical crosslinker to obtain HA hydrogels. Using a new dissolution tester and ketoprofen (KP) as a model drug, we study the release properties of the hydrogels. We obtain homogeneous and transparent hydrogels with high strength and elasticity. The swelling ratio (SR) depends on the crosslinker concentration and pH of the medium. We also reveal differences between the release profile of KP from swollen and unswollen hydrogels. The characteristics and differences in KP release profiles depending on the SR suggest the possibility of obtaining controlled release from HA-based hydrogels. © 2013 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 130: 1377-1382, 2013 [ABSTRACT FROM AUTHOR]

Microemulsions have been revealed as feasible templates to grow magnetic nanostructures using an electrodeposition method. Reducing agents are not required and the applied potential has been used as driving force of the nanostructure growth. A systematic study of conductive microemulsion systems to allow the CoNi electrodeposition process has been performed. Different surfactants and organic components have been tested to form microemulsions with a CoNi electrolytic bath as an aqueous component in order to define the microemulsions showing enough conductivity to perform an electrodeposition process from the aqueous component. By using microemulsions of the aqueous electrolyte solution–Triton X-100–diisopropyl adipate system, CoNi electrodeposition has been achieved, the structure of the deposits being dependent on the composition and structure of the microemulsion, which can act as a soft-template to obtain different discontinuous deposits. The magnetic properties of the CoNi deposits vary with their structure. [ABSTRACT FROM AUTHOR]

A novel and simple single-step method for the preparationof meso/macroporoussilica materials is described, which consists in templating in highlyconcentrated emulsions with a cubic liquid crystal in the continuousphase. Tetraethyl orthosilicate (TEOS) was solubilized in the aqueouscontinuous phase of highly concentrated emulsions stabilized by C12(EO)8and a PEO–PPO–PEO block copolymernonionic surfactant, with a cubic liquid crystalline phase of the Fd3mtype. The resulting silica materialswere characterized by small-angle X-ray scattering, nitrogen sorptionand transmission electron microscopy. The results showed that a dualpore size distribution was obtained, consisting of mesopores in thenanometer range and macropores between 1 and 5 μm. These dualmeso/macroporous silicas with bimodal pore size distribution can possessspecific surface areas higher than 400 m2/g. [ABSTRACT FROM AUTHOR]