Optical Sensing Properties of New Innovative Materials: Interaction of Photoactive Copolymers with Fluorescent Nanoparticles to Create Light-Sensitive Hydrogel Films

This work investigates the use of two photoactive polymers, functionalized with quantum dots (QDs) (ZnS and CdTe/ZnS), to develop optical sensing hydrogel films through their interactions. It examines their responses to light stimulation for potential biological applications. The optical and morphological properties of the films were studied, revealing photoactive surfaces. The photoactive copolymers were synthesized based on poly(maleic anhydride-alt-2-methyl-2-butene), P(MAn-alt-2MB), and poly(maleic anhydride-alt-1-octadecene), P(MAn-alt-OD), by attaching the photochromic agent, 1-(2-hydroxyethyl)-3,3-dimethylindoline-6-nitrobenzo pyran (SP). Subsequently, QD nanoparticles (ZnS or CdTe/ZnS NPs) were incorporated into the polymer solutions in the presence of a crosslinker agent, and were then spin-coated onto glass substrates under suitable conditions to produce porous-patterned films. These films were created using a one-step bio-inspired process called the breath figure (BF) method. SEM images of QD-containing samples show a photoactive porous surface resulting from a synergistic interaction between the components. The reversibility of these macroscopic properties results from photoinduced transformations at the molecular level. The light-emitting properties of the films were characterized by blue and violet fluorescence under UV light. Advances in film-forming techniques enable the creation of functional structures with important applications, such as microstructured hydrogel films for biological uses.