RESUMO
Chemically crosslinked hydrogels based on poly(N-vinylcaprolactam) (PNVCL) were synthetized by a photoinitiated chemical method. A galactose-based monomer, 2-lactobionamidoethyl methacrylate (LAMA), and N-vinylpyrrolidone (NVP) were added with the aim to improve the physical and chemical properties of hydrogels. The effects of both comonomers on the swelling ratio (Q), volume phase transition temperature (VPTT), glass transition temperature (Tg), and Young's moduli by mechanical compression below and above the VPTT were studied. Gold nanorods (GNRDs) and 5-fluorouracil (5FU) were embedded into the hydrogels, to study the drug release profiles with and without the excitation of GNRDs by irradiation in the near-infrared region (NIR). Results showed that the addition of LAMA and NVP increased the hydrogels' hydrophilicity, elasticity, and VPTT. The loading of GNRDs in the hydrogels changed the release rate of 5FU when irradiated intermittently with an NIR laser. The present study reports on the preparation of a hydrogel-based platform of PNVCL-GNRDs-5FU as a potential hybrid anticancer hydrogel for chemo/photothermal therapy that could be applied against skin cancer for topical 5FU delivery.
RESUMO
In this work, the preparation of dense blended membranes, from blends of poly(vinylidene fluoride) (PVDF), poly(ether sulfone) (PES) and polyethyleneimine (PEI) or Fumion®, with possible applications in alkaline fuel cell (AEMFC) is reported. The blended PEI/Fumion® membranes were prepared under a controlled air atmosphere by a solvent evaporation method, and were characterized regarding water uptake, swelling ratio, thermogravimetric analysis (TGA), infrared spectroscopy (FT-IR), scanning electron microscopy (SEM), ion exchange capacity (IEC), OH- conductivity and novel hydroxide ion exchange rate (HIER), which is related to the mass transport capacity of the OH- ions through the membrane. The effect of the chemical composition on its morphological and anion exchange properties was evaluated. It was expected that the usage of a commercial ionomer Fumion®, in the blended membranes would result in better features in the electrical/ionic conductivity behaviour. However, two of the membranes containing PEI exhibited a higher HIER and OH- conductivity than Fumion® membranes, and were excellent option for potential applications in AEMFC, considering their performance and the cost of Fumion®-based membranes.