Self-assembly of Fibres in Alkylcarboxylate—Sodium Silicate Systems

Fibres of macroscopic size (up to 5 cm in length) formed spontaneously in initially homogeneous systems containing alkali metal salts of saturated n-alkylcarboxylic acids and sodium silicate. After drying, these fibres resembled wool or down, with some being in the form of dense strands which laminated into single fibres with time. The minimal thickness of these single fibres was ca. 0.5 mm and, since a dense parallel cluster contained ca. 34 000 micellar strands, the thickness of each fibre plus associated silicate surface layer amounted to ca. 27 Å. It was suggested that the key feature of the self-assembly mechanism is the weak interaction between a surfactant molecule and a silicate leading to the continuous formation of microscopic sized fibres.