title: Swelling and shrinking properties of thermo-responsive polymeric ionic liquid hydrogels with embedded linear pNIPAAM.
abstract: In this study, varying concentrations of linear pNIPAAM have been incorporated for the first time into a thermo-responsive polymeric ionic liquid (PIL) hydrogel, namely tributyl-hexyl phosphonium 3-sulfopropylacrylate (P-SPA), to produce semi-interpenetrating polymer networks. The thermal properties of the resulting hydrogels have been investigated along with their thermo-induced shrinking and reswelling capabilities. The semi-interpenetrating networks (IPN) hydrogels were found to have improved shrinking and reswelling properties compared with their PIL counterpart. At elevated temperatures (50-80 °C), it was found that the semi-IPN with the highest concentration of hydrophobic pNIPAAM exhibited the highest shrinking percentage of ~40% compared to the conventional P-SPA, (27%). This trend was also found to occur for the reswelling measurements, with semi-IPN hydrogels producing the highest reswelling percentage of ~67%, with respect to its contracted state. This was attributed to an increase in water affinity due to the presence of hydrophilic pNIPAAM. Moreover, the presence of linear pNIPAAM in the polymer matrix leads to improved shrinking and reswelling response compared to the equivalent PIL.
authors.affiliation: CLARITY, the Centre for Sensor Web Technologies, National Centre for Sensor Research, School of Chemical Sciences, Dublin City University, Dublin 9, Ireland. simon.gallagher24@mail.dcu.ie.
authors.forename: Simon
authors.initials: S
authors.lastname: Gallagher
authors.affiliation: Insight Centre for Data Analytics, Dublin City University, Dublin 9, Ireland. larisa.florea@dcu.ie.
authors.forename: Larisa
authors.initials: L
authors.lastname: Florea
authors.affiliation: Insight Centre for Data Analytics, Dublin City University, Dublin 9, Ireland. kevin.fraser@dcu.ie.
authors.forename: Kevin J
authors.initials: KJ
authors.lastname: Fraser
authors.affiliation: CLARITY, the Centre for Sensor Web Technologies, National Centre for Sensor Research, School of Chemical Sciences, Dublin City University, Dublin 9, Ireland. dermot.diamond@dcu.ie.
authors.forename: Dermot
authors.initials: D
authors.lastname: Diamond
mesh_terms: D000179:Acrylates / Q000737:chemistry; D000180:Acrylic Resins / Q000737:chemistry; D001672:Biocompatible Materials / Q000737:chemistry*; D006358:Hot Temperature; D020100:Hydrogels / Q000737:chemistry*; D052578:Ionic Liquids / Q000737:chemistry*; D008422:Materials Testing; D011108:Polymers / Q000737:chemistry
chemical_list: D000179:Acrylates; D000180:Acrylic Resins; D001672:Biocompatible Materials; D020100:Hydrogels; D052578:Ionic Liquids; D011108:Polymers; C052970:poly-N-isopropylacrylamide