Equilibrium Phase Diagrams of Interpenetrating Polymer Networks and Liquid Crystals

Abstract

Swelling and deswelling of photochemically crosslinked interpenetrating polymer networks in anisotropic solvents were examined. Phase diagrams were established in terms of composition and temperature using two low-molecularweight nematic liquid crystals, 4-cyano-4-n'-pentylbiphenyl and an eutectic mixture of cyanoparaphenylenes. Networks were formed by ultraviolet curing in the presence of a difunctional monomer and a photoinitiator. Immersion in excess of solvent allowed us to measure the solvent uptake by weight and to determine the size increase by optical microscopy in terms of temperature. We calculated weight and diameter ratios considering the swollen-to-dry network states of the samples.

Photochemical Production of Interpenetrating Polymer Networks; Simultaneous Initiation of Radical and Cationic Polymerization Reactions

“…Different examples can be given: acrylate/epoxide, (e.g., hexanediol diacrylate (HDDA)/3,4-epoxycyclohexylmethyl-3'4' epoxycyclohexyl carboxylate (EPOX)), trimethylolpropane triacrylate (TMPTA)/EPOX, TMPTA/diglycidyl ether of bisphenol A based epoxy resin EP, TMPTA/tri(ethylene glycol) divinyl ether (DVE-3), TMPTA/4-cyclo-hexane dimethanol divinyl ether (CHVE), fluorinated acrylate/epoxide, vinylether/acrylate, vinylether/maleate, vinylether/maleimide or oxetane/acrylate blends, (see e.g., in [19][20][21][22][23][24][25][26][27][28][29][30][31][32][33][34][35]) anthracene-labeled polystyrene/methyl methacrylate MMA/ethylene glycol dimethacrylate [36], polyisobutene/polystyrene [37], polyacrylate/polybenzoxazine [38], acrylic/liquid crystals [39,40], 2-hydroxyethyl methacrylate/N-vinyl-2-pyrrolidone [41], polyurethane/poly(2-hydroxyethyl methacrylate) [42], calcium alginate/dextran-HEMA [43].…”

Stimuli‐Responsive Materials Based on Interpenetrating Polymer Liquid Crystal Hydrogels

“…IPNs based on hydrogels have been reported but the combination of LCs and hydrogels has not been explored . In the latter case, the anisotropic and molecular order of liquid crystals can be combined with the responsive isotropic properties of hydrogels . Here, we report on the preparation of cholesteric liquid crystalline (CLC)‐poly(acrylic acid) hydrogel‐based IPNs, resulting in an anisotropic hydrogel‐like material that exhibits enhanced and combined functional properties.…”

Kinetic analysis of the swelling behavior of poly(n‐butylacrylate‐1,6‐hexanedioldiacrylate) networks in 4‐cyano‐4′‐n‐pentyl‐biphenyl (5CB)

“…in the presence of small LC molecules. [52][53][54][55][56][57][58][59][60] Bouchaour et al 56 studied the swelling properties in the equilibrium state of poly(n-butylacrylate) (PABu) networks in isotropic solvents and LC 4-cyano-4 0 -npentyl-biphenyl (5CB). They considered two photochemically crosslinked polymer networks elaborated using 0.5 and 5 wt % of crosslinking agent.…”

“…Following these lines, research interests were focused on the swelling behavior of mainly photochemically crosslinked polymer networks in the presence of small LC molecules . Bouchaour et al .…”