Thin Film and Bulk Morphologies in Linear Triblock Terpolymers of Polystyrene, Polybutadiene and Poly(dimethylsiloxane)

We investigate the self-assembled microdomain morphologies of three linear triblock terpolymers (TTPs) composed of polystyrene (PS), polybutadiene (PB), and poly(dimethylsiloxane) (PDMS) blocks, focusing on the influence of molecular architecture, molecular weight (Mn) and film thickness on the structure. In the bulk, the terpolymers form gyroid, core–shell or lamellar morphologies but in thin films, the gyroid and core–shell TTPs transition into perforated lamellae (PL), while the lamellar TTP forms interconnected morphologies including vertical cylinders protruding from an underlying layer of PL or in-plane cylinders. The PDMS-rich wetting layer influences film morphology, and surface modification by a poly(vinyl alcohol) topcoat neutralizes the surface energy and facilitates the formation of vertically aligned lamellae. Our results highlight the interplay between molecular design, processing and surface effects in the formation of these thin film nanostructures, expanding opportunities for TTP-derived fabrication.