Morphology evolution of entropy driven supramolecule nanocomposite

Equilibrium morphologies of polymeric nanocomposites, determined by phase diagrams, serve as foundational structures for various applications, including nanoelectronics, optics, and photonic crystals. However, these morphologies, encompassing lamellae, cylinders, spheres, and gyroids, are predominantly constrained within the phase diagrams. This study aims to elucidate the self-assembly pathway of lamellae-forming polymeric nanocomposites and explore intermediate states to facilitate the formation of more complex nanostructures. The system investigated here consisted of high-molecular-weight diblock copolymers, small molecules, and an organic solvent. The small molecules selectively hydrogen bonded to one block of the polymer, transitioning the architecture from coil-coil to coil-comb block copolymers. Additionally, these molecules mediated unfavorable enthalpic interactions between the blocks, driving the assembly process via entropy. Experimental analysis employing transmission electron microscopy and small-angle X-ray scattering revealed intriguing insights. These arrays expanded over microns of domain and gradually evolved into lamellar structures. Multiple pathways, including lateral expansion and sheared expansion, were observed during the evolution from intermediate to equilibrium states, resulting in reduced defect densities in the final structures. By unraveling the complex evolution during assembly in complex blends, our study paves the way for engineering advanced nanostructures with tailored properties.