Effect of Segmental Adsorption on the Tethering of End-Functionalized Polymer Chains

A comparison study was conducted of tethering in a poor solvent, in which segmental adsorption as well as tethering occurred, and tethering in good solvent, in which, for the conditions used, only tethering, and no adsorption, occurred. Monodisperse, amine end-functionalized polystyrene was tethered to the surface of silicate glass by chemical reaction with epoxide reactive sites thereon. The tethering process was monitored in real time by means of a procedure that enabled differentiation between chains held to the surface of the substrate by segmental adsorption alone and chains tethered to it by chemical bonds. The differences between tethering in the absence and presence of segmental adsorption were striking; not only was the kinetics of tethering changed, but also the number of chains tethered per unit surface area was larger (not smaller) and saturation was reached earlier when segmental adsorption occurred.