title: Retention of the original LLC structure in a cross-linked poly(ethylene glycol) diacrylate hydrogel with reinforcement from a silica network.
abstract: Cross-linked poly(ethylene glycol) diacrylate (PEGDA) hydrogels with uniformly controlled nanoporous structures templated from hexagonal lyotropic liquid crystals (LLC) represent separation membrane materials with potentially high permeability and selectivity due to their high pore density and narrow pore size distribution. However, retaining LLC templated nanostructures is a challenge as the polymer gels are not strong enough to sustain the surface tension during the drying process. In the current study, cross-linked PEGDA gels were reinforced with a silica network synthesized via an in situ sol-gel method, which assists in the retention of the hexagonal LLC structure. The silica precursor does not obstruct the formation of hexagonal phases. After surfactant removal and drying, these hexagonal structures in samples with a certain amount of tetraethoxysilane (TEOS) loading are well retained while the nanostructures are collapsed in samples without silica reinforcement, leading to the hypothesis that the reinforcement provided by the silica network stabilizes the LLC structure. The study examines the conditions necessary for a sufficient and well dispersed silica network in PEGDA gels that contributes to the retention of original LLC structures, which potentially enables broad applications of these gels as biomedical and membrane materials.
authors.affiliation: Institute for Frontier Materials, Deakin University, Waurn Ponds, VIC 3216, Australia. lingxue.kong@deakin.edu.au.
authors.forename: Juan
authors.initials: J
authors.lastname: Zhang
authors.forename: Zongli
authors.initials: Z
authors.lastname: Xie
authors.forename: Manh
authors.initials: M
authors.lastname: Hoang
authors.forename: Anita J
authors.initials: AJ
authors.lastname: Hill
authors.forename: Weiwei
authors.initials: W
authors.lastname: Cong
authors.forename: Feng Hua
authors.initials: FH
authors.lastname: She
authors.forename: Weimin
authors.initials: W
authors.lastname: Gao
authors.forename: Ling Xue
authors.initials: LX
authors.lastname: Kong
mesh_terms: D003432:Cross-Linking Reagents / Q000737:chemistry*; D020100:Hydrogels / Q000737:chemistry*; D050866:Liquid Crystals / Q000737:chemistry*; D049329:Nanostructures / Q000737:chemistry; D011092:Polyethylene Glycols / Q000737:chemistry*; D012821:Silanes / Q000737:chemistry; D058428:Silica Gel / Q000737:chemistry*; D013500:Surface Tension; D013501:Surface-Active Agents / Q000737:chemistry
chemical_list: D003432:Cross-Linking Reagents; D020100:Hydrogels; D012821:Silanes; D013501:Surface-Active Agents; C437167:poly(ethylene glycol)diacrylate; D011092:Polyethylene Glycols; C040733:tetraethoxysilane; D058428:Silica Gel