Síntese e Caracterização de Membranas Poliméricas Baseadas em PVA/F127/Grafeno para Aplicações Biomédicas

Abstract

The use of polymers in biomedical applications has stood out due to their versatility in modifying structural and physicochemical properties. Among these materials, polyvinyl alcohol (PVA) is widely employed for its biocompatibility, mechanical strength, and hydrophilicity. Another promising candidate is the copolymer Pluronic F127 (F127), which exhibits thermosensitive behavior and the ability to act as a nanocarrier, thus favoring controlled drug release. When combined with graphene, a nanosheet composed of carbon atoms, the system exhibits enhanced stability, responsiveness, and delivery efficiency. Although the literature reports the performance of binary systems such as PVA/F127 or PVA/graphene, the ternary formulation involving all three components remains scarcely explored. This approach represents a significant advancement by integrating, within a single matrix, adjustable structural, functional, and mechanical properties for topical applications. In this study, a membrane was developed using solvent casting, composed of PVA, F127, and encapsulated graphene in varying proportions, with a focus on optimizing morphological and physicochemical properties. PVA acts as the polymer matrix, while the F127 and graphene combination forms nanostructures dispersed throughout the membrane, inducing morphological alterations characterized by the presence of pores, as revealed by Scanning Electron Microscopy (SEM) and Atomic Force Microscopy (AFM). Increasing the concentration of the copolymer led to reduced crystallinity, although this effect was less pronounced in samples containing graphene due to the appearance of its characteristic peak in X ray Diffraction (XRD) analysis. As the amorphous character increased, a more pronounced plasticizing effect was observed, reflected in the reduction of Young’s modulus, increased tensile strain, and decreased tensile strength. Although no significant changes in the vibrational modes of functional groups were detected among the formulations according to Raman (RS) and Infrared (IR) spectroscopy, an intensification of short range interactions was evidenced by increased adhesion forces in AFM experiments. This behavior favors membrane wettability, as indicated by a decrease in contact angle with increasing F127 content, with or without graphene. Such behavior is associated with the transition to a gel state in the presence of moisture, promoting efficient adhesion to skin tissue. Therefore, the unprecedented integration of PVA, F127, and graphene enabled the development of membranes with optimized structure and performance, showing great potential for application in topical biomedical devices.