In situ AFM observation of heterogeneous growth of adsorbed film on cleaved mica surface

The dynamic process of cationic surfactant molecules to form adsorbed layer on cleaved mica surface was observed in situ for the first time by AFM. At the initial stage of adsorption, the adsorbed molecules are observed as the small island-like aggregates with the size of about 10-30 nm. These islands are replaced by larger patches as time lapses. After the continuous growth of the patches, a close-packed film with uniform appearance is approached. The driving force to increase the size of molecular aggregates may either be by line tension or by two dimensional Laplace pressure that induce coalescence of smaller aggregates into larger patches. (C) 1998 Published by Elsevier Science S.A.