Unveiling the Structural Evolution of Starch-Sodium Salt Complex Membrane: A Morphological Perspective

Abstract

The development of sustainable and biodegradable materials for energy storage and functional applications has gained significant attention. This study aims to investigate the structural evolution and morphological modifications of starch-sodium salt complex membranes, focusing on the impact of sodium methanoate incorporation on the polymer matrix. Solid-state membranes were prepared using a solution casting technique with starch, sodium methanoate, distilled water, and glycerin. The pure membrane exhibited a smooth and transparent surface, indicating a uniform polymer network. However, increasing sodium methanoate concentrations led to notable changes in surface morphology, including enhanced opacity and structural heterogeneity. Characterization using a high-resolution camera, SEM, and EDS confirmed the formation of distinct macro- and microstructures, alongside a uniform distribution of sodium ions within the polymer matrix. Among the tested compositions, the 30 wt.% sodium methanoate membrane exhibited the most optimized structure, with a uniformly distributed opaque appearance, a highly veiny morphology observed in SEM, and an evenly dispersed sodium ion distribution in EDS analysis. These findings contribute to the understanding of salt-mediated structural modifications in starch-based materials, offering insights into their potential applications in biopolymer electrolytes and other advanced materials.