POLYMORPHISM IN ANHYDROUS AMPHIPHILIC SYSTEMS - LONG-CHAIN PRIMARY NORMAL-ALKYLAMMONIUM CHLORIDES

The primary long-chain n-alkylammonium chlorides experience stepwise melting. An x-ray diffractometric investigation showed that the "clear" liq. is reached from the cryst. state through a plastic phase with conformational disorder of the alkyl chains, and a smectic mesophase analogous to the "neat" phase of the anhyd. soaps. The clear liq. itself is a new, less organized smectic mesophase. This melting behavior appears to be common to a wide class of ionic amphiphiles, including the anhyd. alkali-metal n-alkanoates.