Self-assembly of silver nano-particles on stearic acid Langmuir-Blodgett film: evidence of fractal growth

A new technique has been developed to make Langmuir-Blodgett films (LB) on solid substrate containing silver nano-particle clusters. It is based on electrostatic attraction between negatively charged acid groups of stearic acid and positively charged silver nano-particles in silver sol. TEM picture shows that the cluster growth is fractal in nature of dimensions ranging from 1.4 to 1.8 depending on the growth time. After sufficient time of immersion in silver sol, the fractal structure is transformed to lumpy structures. Possible reasons for the formation of silver nano-cluster in LB film are discussed.