Controlling the shape of Janus nanostructures through supramolecular modification of ABC terpolymer bulk morphologies

Abstract

of the original manuscript:Hiekkataipale, P.; Loebling, T.I.; Poutanen, M.; Priimagi, A.; Abetz, V.; Ikkala, O.; Groeschel, A.H.: Controlling the shape of Janus nanostructures through supramolecular modification of ABC terpolymer bulk morphologies In: Polymer (2016 Abstract: Block copolymers microphase separate into a variety of bulk morphologies that serve as scaffolds, templates, masks and source for polymeric nano-particles. While supramolecular additives are common to complex within diblock copolymers to modify the morphology, the subtle effects of complexation on ABC triblock terpolymer morphologies are less explored. Here, we describe the manipulation of polystyrene-block-poly(4-vinylpyridine)-blockpoly(tert-butyl methacrylate) (PS-b-P4VP-b-PT or S4VT) triblock terpolymer bulk morphologies through supramolecular complexation with rod-like 4-(4-pentylphenylazo)phenol (5PAP).The 5PAP molecule hydrogen bonds by phenolic groups to the 4VP repeating units and with increasing molar fraction of 5PAP, initially observed P4VP cylinders flatten into elliptic cylinders until a morphological transition occurs into a third (P4VP/5PAP) lamella. At sufficient 5PAP loadings, the cylinders can even merge into a perforated P4VP lamella located at the PS/PT interface. Quaternization of the P4VP phase and re-dispersion in organic solvent allows liberating S4VT Janus nanostructures from the bulk, including Janus cylinders, nanoporous Janus membranes and Janus sheets. The manipulation of "sandwiched" microphases through supramolecular binding motifs could allow the preparation of previously inaccessible terpolymer bulk morphologies and, in case of cross-linkable phases, lead to a larger library of Janus nano-objects.

Template‐Free Synthesis and Selective Filling of Janus Nanocups

“…[5,29] They found application as nanomotors, [30] interfacial stabilizers, [31,32] and catalysis. [41] Theinherent lack of examples for JNCs [42] underlines the challenge to simultaneously break the symmetry of surface chemistry and shape. [41] Theinherent lack of examples for JNCs [42] underlines the challenge to simultaneously break the symmetry of surface chemistry and shape.…”

Self‐Assembly of Multiblock Copolymers

“…For instance, azobenzene hydrogen bond donors were added in various molar ratios to the P4VP repeating units of PS‐ b ‐P4VP‐ b ‐P t BMA triblock terpolymers, which resulted in a morphological transformation of the P4VP microphase. At f P4VP =12 wt %, P4VP cylinders transformed into perforated lamellae at a loading of 25 mol% azobenzene . According to small angle X‐ray scattering (SAXS) measurements, the perforated lamella morphology had remarkable long‐range order as indicated by equidistant peaks up to the 9 th order.…”

“…Besides adjusting the geometry of the domain between the lamellae synthetically, additives likewise result in subtle morphological changes. The supramolecular loading of P4VP domains of PS‐ b ‐P4VP‐ b ‐P t BMA with azobenzene molecules allowed to alter the P4VP cylinders to a hexagonally‐perforated P4VP lamella . Subsequent quaternization of the P4VP microdomain to P4VPMe + /I − and redispersion in toluene, liberated perforated Janus nanosheets from the bulk phase due to the insoluble and permanently charged P4VPMe + /I − mesh.…”

Supramolecular design principles for efficient photoresponsive polymer–azobenzene complexes

“…147 However, none of the BCP complexes they prepared involved azobenzene guests. On the other hand, Xu and co-workers, 148 Stamm and coworkers, [149][150][151] and, recently Gröschel and coworkers, 152 have used azobenzene-containing hydrogenbonded side chains in investigations involving thin-film nanopatterning, nanoparticle assembly, and templating with supramolecular BCPs, but they did not explore the potential photoresponsive properties of these complexes. Photoinduced control over the phase structure of BCP materials combined with supramolecularly bonded azobenzene molecules is a highly interesting phenomenon, which has only recently begun to be explored.…”