title: Composite hydrogels of polyacrylamide and crosslinked pH-responsive micrometer-sized hollow particles.
abstract: Whilst hydrogels and hollow particles both continue to attract much attention in the literature there are few examples of hydrogel composites containing hollow particles. Here, we study composite polyacrylamide (PAAm) hydrogels containing micrometer-sized pH-responsive shell-crosslinked hollow particles (abbreviated as HPXL) based on poly(methylmethacrylate-co-methacrylic acid) functionalised with glycidyl methacrylate (GMA). The HPXL particles were prepared using our scaleable emulsion template method and inclusion of GMA was found to promote spherical hollow particle formation. The pendant vinyl groups from GMA enabled shell-crosslinked hollow particles to be prepared prior to formation of the PAAm/HPXL composite gels. The morphologies of the particles and composite gels were studied by optical microscopy, confocal laser scanning microscopy and scanning electron microscopy. Dynamic rheology measurements for the composite gels showed that the modulus variation with HPXL concentration could be described by a percolation model with a HPXL percolation threshold concentration of 4.4 wt% and a scaling exponent of 2.6. The composite gels were pH-responsive and largely maintained their mechanical properties over the pH range 4.0 to 8.0. Because the composite gels had tuneable mechanical properties (with modulus values up to 530 kPa) and were pH-responsive they are potential candidates for future wound healing or membrane applications.
authors.affiliation: Biomaterials Research Group, School of Materials, The University of Manchester, MSS Tower, Manchester, M13 9PL, UK. brian.saunders@manchester.ac.uk.
authors.forename: Kyriaki
authors.initials: K
authors.lastname: Pafiti
authors.affiliation: Biomaterials Research Group, School of Materials, The University of Manchester, MSS Tower, Manchester, M13 9PL, UK. brian.saunders@manchester.ac.uk.
authors.forename: Zhengxing
authors.initials: Z
authors.lastname: Cui
authors.affiliation: Biomaterials Research Group, School of Materials, The University of Manchester, MSS Tower, Manchester, M13 9PL, UK. brian.saunders@manchester.ac.uk.
authors.forename: Louise
authors.initials: L
authors.lastname: Carney
authors.affiliation: Division of Regenerative Medicine, School of Medicine, Stopford Building, The University of Manchester, Oxford Road, Manchester, M13 9PT, UK.
authors.forename: Anthony J
authors.initials: AJ
authors.lastname: Freemont
authors.affiliation: Biomaterials Research Group, School of Materials, The University of Manchester, MSS Tower, Manchester, M13 9PL, UK. brian.saunders@manchester.ac.uk.
authors.forename: Brian R
authors.initials: BR
authors.lastname: Saunders
mesh_terms: D000180:Acrylic Resins / Q000737:chemistry*; D002214:Capsules / Q000737:chemistry; D003432:Cross-Linking Reagents / Q000737:chemistry; D004548:Elasticity; D020100:Hydrogels / Q000737:chemistry*; D006863:Hydrogen-Ion Concentration; D011109:Polymethacrylic Acids / Q000737:chemistry; D000099166:Polyacrylamides
chemical_list: D000180:Acrylic Resins; D002214:Capsules; D003432:Cross-Linking Reagents; D020100:Hydrogels; D011109:Polymethacrylic Acids; D000099166:Polyacrylamides; C038300:methylmethacrylate-methacrylic acid copolymer