When Soft Matter Goes Really Soft – A New Paradigm for Star Polymer Self-Assembly

ended

Biologic supramolecular assemblies, e.g., virus capsids and multiprotein complexes, show unprecedented complexity compared to man-made structures. A key feature of the building blocks facilitating the emergence of this structural complexity is their deformability. This enables them to reconfigure during assembly to find optimum orientations within the superstructure. Here, I propose to exploit the concept of reconfigurability as design criterion for developing a new class of colloidal building blocks. Where currently available hard particles fail to form macroscopic structures due to lack of building block uniformity and undesired metastable states encountered during assembly, introducing flexibility will prevent these adverse characteristics. The envisioned building blocks are based on polymer grafted cores, where the attached polymers arms comprise solvophilic and solvophobic blocks. The limited number of arms have significant conformational freedom, a feature absent in traditional hard particles. The solvophobic segments, located at the particle’s periphery, drive spontaneous polymer micro-phase separation into patchy domains which are then locked into place. These patches imprint directional interactions to guide self-assembly and are linked to the core via flexible solvophilic polymers, enabling patch fluctuations. The resulting patch adaptability prevents the system from getting trapped in non-equilibrium states and relaxes stringent requirements on geometric uniformity, promoting the formation of long-range ordered assemblies. Following simulation studies, these soft particles should have propensity to order into ‘open’ (quasi)crystalline lattices providing unique photonic, mechanical and porous characteristics. Complementing my physical/polymer synthetic background with pioneering analytic tools, e.g. time-resolved scattering and in situ electron microscopy, this project will detail a new paradigm for self-assembly and the importance of patch flexibility.