Defining Morphological Transformations of “Soft Nature” Diblock Viscoelastic Structured Polymers

Structured diblock copolymer liquids consisting exclusively of “soft” segments with glass-transition temperatures well below room temperature have not been studied extensively in the literature in terms of self-assembly properties to date. Despite their “soft nature”, these types of diblock copolymers are capable of forming well-ordered topologies at low temperatures. This ability is attributed to their low dispersity indices (Đ) and relatively high Flory–Huggins interaction parameter, χ, between the chemically different involved blocks. Herein, we report a comprehensive study of the synthesized copolymers on molecular and thermal characterization, along with the structure–property relationship of two types of polydiene-b-polysiloxane copolymers by manipulating the monomer’s ratio during synthesis. Emphasis was given to the self-assembly behavior when the molecular characteristics (volume fraction and degree of polymerization) of the involved blocks varied to assess the limits of the phase stability. Specially, poly(butadiene) (PB1,2) or poly(isoprene) (PI1,4) was utilized as the first segment, while poly(dimethylsiloxane) (PDMS) was used as the second block in all cases. The molecular characteristics’ diversity combined with the ability to design/synthesize block copolymers with well-ordered phases ranging from spheres, cylinders, lamellar, and finally network structures is quite promising for nanotechnology applications in soft electronics. Also, the inherent properties of the copolymers, such as thermal stability, hydrophobicity, and flexibility, render them potential candidates for stretchable and/or wearable applications.