Coarse-Grained Molecular Simulation of Bolapolyphiles with a Multident Lateral Chain: Formation and Structural Analysis of Cubic Network Phases

YY Sun and FA Escobedo, JOURNAL OF CHEMICAL THEORY AND COMPUTATION, 20, 1519-1537 (2023).

DOI: 10.1021/acs.jctc.3c00395

Bolapolyphilesconstitute a versatile class of materials with ademonstrated potential to form a wide variety of complex ordered mesophases.In particular, cubic network phases (like the gyroid, primitive, anddiamond phases) have been a target of many studies for their abilityto create percolating 3D nanosized channels. In this study, molecularsimulations are used to explore the phase behavior of bolapolyphilescontaining a rigid rodlike core, associating hydrophilic core endsand a hydrophobic side chain with a multident architecture, i.e.,where the branching pattern can vary from bident (two branches) tohexadent (six branches). Upon network phase formation, its skeletonis made up of "nodes" populated by the core ends and"struts" populated by the cores. It is shown that, byvarying the side chain length, branching pattern, and attachment pointto the core, one can alter the crowding around the cores and hencetune the nodal size and nodal valence (i.e., number of connectingstruts) which lead to different types of network morphologies. Forexample, for a fixed total side chain length, having more branchesgenerates a stronger crowding around the molecular core, driving themto form bundlelike domains with curvier interfaces that result inthinner struts. Also, attaching the lateral chain closer to one coreend breaks the symmetry between the environments around the two coreends, leading to networks with bimodal nodal sizes. Importantly, sincethe characterization of (ordered or partially ordered) network phasesis challenging given the potential incompatibilities between the simulationbox size with the structure's space group periodic symmetryand the effect of morphological defects, a detailed framework is presentedto analyze and fully characterize the unit cell parameters and structurefactor of such systems.

Return to Publications page