A STUDY OF THE EFFECT OF CHAIN-LENGTH ON NEAREST NEIGHBOR INTERACTIONS OF IMMOBILIZED SPECIES

The effect of varying the length and hydrophobicity of the molecular tether that binds an indicator to a substrate was studied. The length or hydrophobicity of the tether may affect the characteristics of the immobilized indicator in several ways. Of primary interest in this study was the extent to which the tether characteristics control interactions between adjacent immobilized species. We investigated two straight-chain tethers of variable length and two branched-chained tethers of different hydrophobicities. For each of these systems, we investigated nearest neighbour interactions as a function of surface coverage. The extent of this interaction was determined by measuring the degree of coupling between adjacent immobilized aromatic diazonium ions. Our results suggest that nearest neighbour interactions between immobilized species in an aqueous environment are controlled primarily by the hydrophobicity of the tether.