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Thermo-responsive poly(ionic liquid) hydrogel microfluidic valves

Tudor, Alexandru and Saez, Janire and Florea, Larisa and Benito-Lopez, Fernando and Diamond, Dermot (2016) Thermo-responsive poly(ionic liquid) hydrogel microfluidic valves. In: Conference on Analytical Sciences Ireland 2016 – 8th CASi, 14-15 Apr 2016, Dublin City University, Dublin, Ireland.

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Several phosphonium ionic liquid monomers have been shown to possess a lower critical solution temperature [1][2]. This property was kept when the monomers were used to synthesize both linear and crosslinked polymers, thus making them suitable materials for the synthesis of stimuli-responsive hydrogels [2]. Herein, we present the synthesis of a thermo-responsive tributylhexyl phosphonium 3-sulfopropyl acrylate (PSPA) crosslinked PIL, followed by its inclusion in a microfluidic device to be used as a temperature controlled valve. The hydrated hydrogels had their temperature-induced shrinking measured with a digital microscope from 20 °C to 70 °C, in 10 °C intervals. Measurements indicate a relative surface contraction of the hydrogels, in deionized water, of 34.04% ± 4.62% (n = 3) at 50 °C, and 53.37% ± 12.55% (n = 3) at 70 °C. Following this, hydrogels were polymerized in a microfluidic chip and had their flow characteristics analysed. When placed on a heating element and connected to a syringe pump and a flow microsensor, the hydrogels allowed deionized water to flow through the microfluidic chip at a rate of 140 nL·min-1 at 50 °C and ~ 15 nL·min-1 at 25 °C. The required time for the PILc valve to open was ~6s, while the time required for it to close was ~8s. In conclusion, the results confirm the applicability of PSPA hydrogels as thermally controlled valves in microfluidic devices. Furthermore, the study will continue by focusing on the optimization of the valve geometry to ensure higher flowrates, while also increasing the lifetime of the valve.

Item Type:Conference or Workshop Item (Poster)
Event Type:Conference
Uncontrolled Keywords:Polymer Chemistry; Microfluidics; Smart Materials; Smart Polymers; Thermo-responsive polymers; ionic liquids; poly(ionic liquid)s
Subjects:Physical Sciences > Organic chemistry
Physical Sciences > Chemistry
DCU Faculties and Centres:DCU Faculties and Schools > Faculty of Science and Health > School of Chemical Sciences
Research Initiatives and Centres > INSIGHT Centre for Data Analytics
Research Initiatives and Centres > National Centre for Sensor Research (NCSR)
Use License:This item is licensed under a Creative Commons Attribution-NonCommercial-Share Alike 3.0 License. View License
ID Code:21183
Deposited On:11 May 2016 10:41 by Alexandru Tudor. Last Modified 11 May 2016 10:41

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