title: Poly(Ionic Liquid) Semi-Interpenetrating Network Multi-Responsive Hydrogels.
abstract: Herein we describe poly(ionic liquid) hydrogel actuators that are capable of responding to multiple stimuli, namely temperature, ionic strength and white light irradiation. Using two starting materials, a crosslinked poly ionic liquid (PIL) and a linear poly(N-isopropylacrylamide-co-spiropyran-co-acrylic acid), several semi-interpenetrating (sIPN) hydrogels were synthesised. The dimensions of hydrogels discs were measured before and after applying the stimuli, to quantify their response. Samples composed of 100% crosslinked PIL alone showed an average area reduction value of ~53% when the temperature was raised from 20 °C to 70 °C, ~24% when immersed in 1% w/w NaF salt solution and no observable photo-response. In comparison, sIPNs containing 300% w/w linear polymer showed an average area reduction of ~45% when the temperature was raised from 20 °C to 70 °C, ~36% when immersed in 1% NaF w/w salt solution and ~10% after 30 min exposure to white light irradiation, respectively. Moreover, by varying the content of the linear component, fine-control over the photo-, thermo- and salt response, swelling-deswelling rate and mechanical properties of the resulting sIPN was achieved.
authors: Insight Centre for Data Analytics, National Centre for Sensor Research, School of Chemical Sciences, Dublin City University, Dublin, Dublin 9, Ireland. alexandru.tudor2@mail.dcu.ie.
authors: Alexandru
authors: A
authors: Tudor
authors: Insight Centre for Data Analytics, National Centre for Sensor Research, School of Chemical Sciences, Dublin City University, Dublin, Dublin 9, Ireland. larisa.florea@dcu.ie.
authors: Larisa
authors: L
authors: Florea
authors: Insight Centre for Data Analytics, National Centre for Sensor Research, School of Chemical Sciences, Dublin City University, Dublin, Dublin 9, Ireland. simon.gallagher24@mail.dcu.ie.
authors: Simon
authors: S
authors: Gallagher
authors: Insight Centre for Data Analytics, National Centre for Sensor Research, School of Chemical Sciences, Dublin City University, Dublin, Dublin 9, Ireland. john.burns9@mail.dcu.ie.
authors: John
authors: J
authors: Burns
authors: Insight Centre for Data Analytics, National Centre for Sensor Research, School of Chemical Sciences, Dublin City University, Dublin, Dublin 9, Ireland. dermot.diamond@dcu.ie.
authors: Dermot
authors: D
authors: Diamond
mesh_terms: D001672:Biocompatible Materials / Q000737:chemistry; D020100:Hydrogels / Q000737:chemistry*; D052578:Ionic Liquids / Q000737:chemistry*; D007477:Ions / Q000737:chemistry; D009994:Osmolar Concentration; D011108:Polymers / Q000737:chemistry*; D013696:Temperature
chemical_list: D001672:Biocompatible Materials; D020100:Hydrogels; D052578:Ionic Liquids; D007477:Ions; D011108:Polymers
keywords: LCST; hydrogels; poly(ionic liquid)s; polyelectrolyte effect; smart materials; stimuli-responsive