-PMMA for Neutral Layer

Polymer chains are irreversibly physisorbed (physically adsorbed) onto impenetrable substrates by intermolecular forces (i.e. H-bonding, vdW force or dipole moment), as the chains favor the conformations which maximizes the segmental contact to compensate the conformational entropy loss. In this study, we succeeded in guiding perpendicular microdomains of polystyrene-b-poly(methyl methacrylate) (PS-b-PMMA) film with the aid of the irreversibly-adsorbed neutral layer made of PS-b-PMMA and evaluated its compositional randomness in terms of the correlation length (ξ) between the two phases of PS and PMMA. This method is widely applicable to various substrates without any necessity of random copolymer brushes or mats other than PS-b-PMMA itself.