Solar-powered reverse osmosis (PV-RO) is a promising solution to address global water scarcity challenges sustainably. This study explores the development and performance of high permeability, temperature-sensitive membranes for enhanced PV RO desalination. Two surface modification techniques were used: (i) polyamide-chitosan composite formation and (ii) oxidative treatment with potassium per sulfate and sodium hypochlorite. These modifications aimed to enhance flux, selectivity, and hydrophilicity. The chitosan-modified membrane demonstrated a 5.56% increase in flux per °C temperature rise, significantly outperforming conventional TFC membranes. Morphological and chemical analyses, including AFM, FTIR, SEM, and zeta potential, confirmed the formation of hydrophilic supramolecular assemblies that enhanced water transport and maintained high salt rejection. Optimal results were obtained with 1000 mg/L chitosan treatment after sodium hypochlorite exposure, achieving over 129% increase in flux with minimal compromise in rejection. These findings position modified membranes as viable candidates for low-energy, high-efficiency solar desalination.