Small angle x-ray scattering experiments on three model low molar mass diblock copolymer systems containing minority polylactide and majority hydrocarbon blocks demonstrate that conformational asymmetry stabilizes the Frank-Kasper σ phase. Differences in block flexibility compete with space filling at constant density inducing the formation of polyhedral shaped particles that assemble into this low symmetry ordered state with local tetrahedral coordination. These results confirm predictions from self-consistent field theory that establish the origins of symmetry breaking in the ordering of block polymer melts subjected to compositional and conformational asymmetry.
Artificial water channels are synthetic molecules that aim to mimic structural and functional features of biological water channels (aquaporins). Here, we report on a cluster-forming organic nanoarchitecture, peptide-appended hybrid[4]arene (PAH[4]), as a new class of artificial water channels. Fluorescence experiments and simulations demonstrated that PAH[4]s can form clusters
This work details the phase behavior of a pseudoternary polymer blend system containing poly(ethylene oxide) (PEO) and polystyrene (PS) homopolymers, a PS−PEO block copolymer, and lithium bis(trifluoromethane)sulfonamide (LiTFSI). The phase behavior of the system is described along the volumetrically symmetric isopleth at a fixed LiTFSI concentration relative to the PEO component. The addition of LiTFSI dramatically increases the segregation strength of the blend, causing the otherwise globally disordered blends to exhibit a variety of microstructured morphologies typically found in salt-free ternary polymer blends, such as lamellae, a hexagonal phase, and a bicontinuous microemulsion. The breadth of morphologies and segregation strengths that can be accessed in this system by simply tuning blend composition establishes a new framework for the design of future ternary blend systems and, more broadly, polymeric materials where microstructured, wellsegregated domains with tunable ion transport properties are desirable.
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