Adsorption kinetics of random copolymers with tunable monomer sequences onto flat surfaces

We report on the adsorption kinetics of heteropolymers with adjustable monomer sequences (HAMS) on flat substrates. Poly(styrene-co-4-bromostyrene) (PBr$_{x}$S) HAMS, where x denotes the mole fraction of 4-bromostyrene (4-BrS), have been prepared by brominating parent polystyrene chains. By adjusting the solvent quality during the bromination reaction a series of PBr$_{x}$S HAMS has been prepared that posses random (good solvent) or random-blocky (poor solvent) distribution of 4-BrS units. We studied the adsorption of PBr$_{x}$S HAMS from various solvents onto flat silica surfaces, where the 4-BrS units possess strong affinity towards silica while the interaction between styrene and the surface is nearly athermal. For a given solvent, the amount of PBr$_{x}$S HAMS adsorbed onto the surface increases with increasing the 4-BrS content and the blockiness in the monomer distribution. Concurrently, the amount of PBr$_{x}$S HAMS on the substrate also increases with decreasing the quality of the solvent from which the copolymer is adsorbed.