The influence of adsorbate-surface interaction energy on adsorption and recognition of diblock copolymers on...

The adsorption and pinning of a single diblock chain on patterned surfaces with varying block-surface interactions are investigated using Monte Carlo simulations. Previous investigations [K. Sumithra and E. Straube, J. Chem. Phys. 125, 154701 (2006)] on diblock copolymers on stripe-patterned surfaces have shown that the adsorption takes place in two stages for certain specific adsorbate-surface interactions. We have found that interesting changes from the usual adsorption behavior occurs for a series of interaction parameters for the copolymer on the surface patterns. It is also seen that the junction point of the different blocks gets pinned to the interface between the different surface sites. It is possible to get the polymer blocks completely localized on respective sites by suitably adjusting the polymer-surface interactions. We find that unlike in the random heteropolymer adsorption on random surface where the second transition is the result of the rearrangement of the already adsorbed polymers, in this case, it is seen that the process not only involves rearrangement but also optimizes the energetics of the chain by optimizing the extent of adsorption. The static and conformational properties of the copolymer are also discussed.