Title: Crystallization morphology and self-assembly of polyacrylamide solutions during evaporation

Abstract: This study investigated crystallization and self-assembly phenomena in polyacrylamide (PAM) solutions during evaporation. As the solvent gradually evaporated, microscopic crystals began to form in the solution. The results show that concentration gradients form as the solution evaporates, leading to varied crystalline morphologies. From the edge to the center of the PAM solution, grass-like structures with intricate vein-like patterns and irregular morphologies were formed. The concentration gradient played a crucial role in this process. The relationship between the concentration gradient and crystalline structures was elucidated using absorbance spectroscopy. Schematics and absorbance spectra illustrate the evolution of the crystallization stages. Our findings not only contribute to a fundamental understanding of colloidal self-assembly but also hold significant implications for various applications, including thin-film fabrication, drug delivery, and nanotechnology.