Formation of Dense Cellulose Monolayers on Silver Surfaces

Abstract

The adsorption of a new cellulose derivative, 6-O-(2,3-bis(thiosulfato)propyl-oxy-2-hydroxy-propyl)-cellulose (TSHP), onto silver surfaces was investigated by means of ellipsometry, contact angle measurements and X-ray photoelectron spectroscopy (XPS). The results showed that the formation of a dense TSHP monolayer on silver surfaces is an irreversible and slow process. Based on XPS results a model was proposed to explain the chemisorption of TSHP on silver substrates. This model considers the homolytical cleavage of the thiosulfate groups attached to the cellulose chains with the formation of thio radicals, which bind covalently to the silver surface. The formation of silver thiolates lead to a stable TSHP monolayer on silver surfaces.