The Physical-Organic Chemistry of Surfaces, and Its Relevance to Molecular Recognition

Abstract : Understanding the interactions between liquids and the surfaces of organic solids is important for the study of molecular recognition. One method for studying these interactions is based on a physical organic approach: formation of well characterized organic surfaces and comparison of the contact angles of liquids on these surfaces. The technique of self-assembly provides an excellent route for the syntheses of organic surfaces; alkanethiols, for example, self-assemble from solutions to form monolayers on gold. Properties of these monolayers, including their thickness and their wettability by water, can be controlled by manipulating the structure and functionality of the molecules used to form the monolayer. The wettability of monolayers on gold formed from HS(CH2)(n)CH3 or HS(CH2)110(CH2)(n)CH3, where n is the number of methylene groups, depends only on the composition the outermost 5-10 A angstroms of the monolayer. The wettability of monolayers formed from mixtures of HS(CH2)11CH3 and HS(CH2)21CH3 depends both on the structure of the outermost part of the monolayer and the structure of the liquid. These and other results suggest that this physical-organic approach has and will continue to provide valuable insight into molecular recognition. Keywords: Biocompatibility, Proteins, Ligands, Biochemistry. (AW)