Chitosan-sulfated titania composite membranes were prepared, characterized, and evaluated for potential application as polymer electrolyte membranes. To improve the chemical stability, the membranes were cross-linked using sulfuric acid, pentasodium triphosphate, and epoxy-terminated polydimethylsiloxane. Differences in membranes’ structure, thickness, morphology, mechanical, and thermal properties prior and after cross-linking reactions were evaluated. Membranes’ water uptake capacities and their chemical stability in Fenton reagent were also studied. As proved by dielectric spectroscopy, the conductivity strongly depends on cross-linker nature and on hydration state of membranes. The most encouraging results were obtained for the chitosan-sulfated titania membrane cross-linked with sulfuric acid. This hydrated membrane attained values of proton conductivity of 1.1 × 10−3 S/cm and 6.2 × 10−3 S/cm, as determined at 60 °C by dielectric spectroscopy and the four-probes method, respectively.

The paper deals with new approaches to chitosan (CS)-based antifungal therapeutic formulations designed to fulfill the requirements of specific applications. Gel-like formulations were prepared by mixing CS dissolved in aqueous lactic acid (LA) solution with nystatin (NYS) powder and/or propolis (PRO) aqueous solution dispersed in glycerin, followed by water evaporation to yield flexible mesoporous (pore widths of 2–4 nm) films of high specific surfaces between 1 × 103 and 1.7 × 103 m2/g. Morphological evaluation of the antifungal films showed uniform dispersion and downsizing of NYS crystallites (with initial sizes up to 50 μm). Their mechanical properties were found to be close to those of soft tissues (Young’s modulus values between 0.044–0.025 MPa). The films presented hydration capacities in physiological condition depending on their composition, i.e., higher for NYS-charged (628%), as compared with PRO loaded films (118–129%). All NYS charged films presented a quick release for the first 10 min followed by a progressive increase of the release efficiency at 48.6%, for the samples containing NYS alone and decreasing values with increasing amount of PRO to 45.9% and 42.8% after 5 h. By in vitro analysis, the hydrogels with acidic pH values around 3.8 were proven to be active against Candida albicans and Candida glabrata species. The time-killing assay performed during 24 h on Candida albicans in synthetic vagina-simulative medium showed that the hydrogel formulations containing both NYS and PRO presented the faster slowing down of the fungal growth, from colony-forming unit (CFU)/mL of 1.24 × 107 to CFU/mL < 10 (starting from the first 6 h).

The spinel ferrite CoFe 1.98 Sm 0.02 O 4 , prepared by solegel autocombustion technique using maleic acid as combustion agent, was successfully functionalized with chitosan (CS) and epichlorohydrine (ECH). The insertion of the samarium cations into the spinel matrix was proved by X-ray diffraction and Fourier transform infrared analyses. Likewise, the specific magnetization value indicated supplementary evidence of the successful adaptation of rare-earth cations into the spinel structure. The functionalization with CS and the crosslinking with ECH were demonstrated by infrared spectroscopy. The developed material (CoFe 1.98 Sm 0.02 O 4 @CS-ECH) was applied as sorbent for the removal of anionic dye (Orange II) in the batch mode. Adsorption process was investigated by kinetics, equilibrium, and thermodynamic studies. The model-based optimization of the adsorption process was performed according to the response surface methodology to evaluate the influence of pH and sorbent dosage. The optimization yielded the maximum value of color removal efficiency of 96.31% using only 1.60 g/L adsorbent dosage at pH 5.2.