  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.
