Verification of the Influence of the 2-Hydroxy-2-methylpropiophenone (Photoinitiator) Content in Hydrogel Materials on Their Physicochemical Properties and Surface Morphology

Currently, hydrogel materials are being widely developed and investigated. Factors affecting their properties may be mentioned, such as the types and the amounts of the reagents used for the synthesis of the hydrogel matrix and modifiers; thus, the main aim of the investigations was to check the impact of the amount of photoinitiator applied during the UV-induced polymerization of polyvinylpyrrolidone-based hydrogels incorporated with vitamin C and Aloe vera juice. The experiments that were performed were focused on determining the hydrogels’ swelling capability, behavior in simulated body fluids, hydrophilicity, chemical structure (using FT-IR spectroscopy), as well as their surface morphology and roughness. It was proven that developed materials had relatively rough surfaces, they did not degrade in simulated physiological liquids, and their swelling ratios in these media were 2.0–3.0 g/g. The only change in the pH of the incubation media—a slight decrease—was caused by the release of the modifiers into the tested liquids. Subsequently, it was demonstrated that as the amount of the photoinitiator (2-hydroxy-2-methylpropiophenone) increased, the percentage elongation decreased, and the tensile strength increased. The content of the photoinitiator in the hydrogels also influenced their wettability. All samples showed hydrophilicity; the more photoinitiator in the hydrogel structure, the lower wetting angle for water. Moreover, the greater the amount of 2-hydroxy-2-methylpropiophenone, the smoother and more homogeneous the hydrogel surface; thus, considering the demonstrated physicochemical properties of developed materials, they seem to show application potential for more advanced research regarding the development of innovative dressing materials.