Conformational transitions of poly(β‐benzyl L‐aspartate)

Conditions that affect the conformation of poly(β‐benzyl L‐aspartate) in films have been studied. A slow transition from the left‐handed to the right‐handed α‐helical form is observed under certain conditions in half‐dried film cast from chloroform solutions and after exposure of amorphous films of the left‐handed β‐helical form to chloroform vapor. This transition is caused by adsorption of moisture. Thermal transitions of these films were examined by differential scanning calorimetry and infrared spectroscopy. The right‐handed α‐helices change to left‐handed ω‐helices around 140°C, and sharp exothermic peak is observed in this region for some films.