Mechanochemistry and ion exchange

The swelling behavior of crosslinked gels of polymethacrylic acid, partially or wholly neutralized by mixtures of sodium and barium hydroxide, is described. At high degrees of neutralization and high barium content there is a contractile region of rapid transition from a swollen to an unswollen state. A new type of contractile polyacid fiber made of Krilium and polyvinyl alcohol was developed. The force–elongation curves are given for these fibers at different degrees of neutralization with sodium and barium hydroxide in solutions containing sodium and barium chloride of various ionic strength. The dimensional changes caused by ion exchange can be utilized in a mechanochemical engine. An irreversible work cycle for such an engine is described in which the energy of mixing of mono- and divalent ions on polyelectrolyte fibers is partially converted into mechanical work.