Radical polymerization behavior and molecular weight development of homologous monoacrylate monomers in lyotropic liquid crystal phases

Abstract

Polymerization in highly ordered lyotropic liquid‐crystalline (LLC) media enables controllable synthesis of polymers possessing interesting nanostructure and physical properties. This study investigates the radical polymerization rate and molecular weight (MW) development of monoacrylates of different aliphatic tail length in a range of LLC phases. Polymerization rate data were acquired using photodifferential scanning calorimetry, and linear polymer MW was determined with gel permeation chromatography. Polymerization occurs much more rapidly, and higher MW is attained in the ordered LLC phases relative to isotropic solutions and neat polymerization. These properties change significantly as a function of LLC phase and monomer structure. A direct relationship is observed between polymer MW formation and the polymerization rate. Definitive changes in rate and MW were observed at phase boundaries, indicating the important role of solvent order. This study demonstrates how solvent ordering effects can be used to control polymer MW and rate of polymerization. © 2015 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2016, 54, 144–154

Photopolymerization kinetics in and of self‐assembling lyotropic liquid crystal templates

“…Due to the significant impact of LLC order on the photopolymerization kinetics, differences in the molecular weight for linear polymers based on the phase geometry of the parent template are expected to give insight into the unique dynamics of polymerization in ordered LLC geometries. These differences have been measured experimentally by characterization of polymerization kinetics and molecular weight for several different LLC/monomer combinations . In one study, differences in the weight average molecular weights of up to 10 5 g/mol were found by changing the order of the LLC phase from cubic to hexagonal while holding other reaction conditions constant .…”

“…As shown in Figure (A), the molecular weight of poly(methyl acrylate) increases as LLC order increases. This finding corresponds to the expected and measured polymerization rate, which also increases with increasing surfactant concentration . Conversely, the molecular weight of poly( n ‐hexyl acrylate), which is more hydrophobic than poly(methyl acrylate), decreases as LLC order increases [Fig.…”

“…Typically, spherical micelles are formed at low surfactant concentration and the hexagonal, bicontinuous cubic, and lamellar mesophases are formed with increasing surfactant concentration (Fig. ) . Such increases in surfactant concentration correspond to increases in orientational ordering and phase continuity (i.e., “long‐range” order).…”

“…DePierro, C. Baguenard and C.A. Guymon, Radical polymerization behavior and molecular weight development of homologous monoacrylate monomers in lyotropic liquid crystal phases, p. 144‐154, Copyright 2016, with permission from John Wiley and Sons …”

Manipulating the Surface Structure of Hybrid UV Curable Coatings through Photopolymerization‐Induced Phase Separation: Influence of Inorganic Portion and Photoinitiator Content

“…Several studies were conducted to manipulate PIPS to obtain a tailored phase separated structure to be utilized in applications such as membranes,[3e,g,j,8] liquid‐crystal displays, and biomedical,[1a] and dental restorative materials . Several studies have been performed on porous materials and monoliths designed by a sol–gel process accompanied by phase separation.…”