Tandem Osmotic Engine Based on Hydrogel Particles with Antipolyelectrolyte and Polyelectrolyte Effect Fuelled by Both Salinity Gradient Modes

Anjali Cheeramthodi Padmanabhan; Dong Suk Han; Sifani Zavahir; Jan Tkac; Peter Kasak

doi:10.3390/gels7040232

Tandem Osmotic Engine Based on Hydrogel Particles with Antipolyelectrolyte and Polyelectrolyte Effect Fuelled by Both Salinity Gradient Modes

Gels. 2021 Nov 25;7(4):232. doi: 10.3390/gels7040232.

Authors

Anjali Cheeramthodi Padmanabhan¹, Dong Suk Han^{1

2}, Sifani Zavahir¹, Jan Tkac³, Peter Kasak¹

Affiliations

¹ Center for Advanced Materials, Qatar University, Doha P.O. Box 2713, Qatar.
² Department of Chemical Engineering, College of Engineering, Qatar University, Doha P.O. Box 2713, Qatar.
³ Institute of Chemistry, Slovak Academy of Sciences, Dubravska Cesta 9, 84538 Bratislava, Slovakia.

Abstract

In this study, we propose a new approach to attain energy by salinity gradient engines with pistons based on hydrogels possessing polyelectrolyte and antipolyelectrolyte effects in a tandem arrangement, providing energy in each salinity gradient mode in a repeatable manner. The swelling of hydrogel with a polyelectrolyte effect and shrinking of hydrogel particles possessing an antipolyelectrolyte effect in desalinated water, and subsequent shrinking of hydrogel with polyelectrolyte and swelling of hydrogel antipolyelectrolyte effect in saline water, generate power in both increasing and decreasing salinity modes. To investigate the energy recovery, we scrutinized osmotic engine assemblies by a setup arrangement of pistons with hydrogel particles, with polyelectrolyte and antipolyelectrolyte effects, in tandem. The energy recovery from the tandem engine setup (calculated based on dry form for each polyelectrolyte polyacrylate-based hydrogel-SPA) and antipolyelectrolyte-sulfobetaine-based gel with methacrylate polymeric backbone-SBE) up to 581 J kg^-1 and a mean power of 0.16 W kg^-1 was obtained by the tandem setup of SPA and SBE hydrogel containing 3% crosslinking density and particle size of 500 microns with an external load of 3.0 kPa. Exchange of sulfobetaine with methacrylamide (SBAm), the main polymer backbone, revealed a positive increase in energy recovery of 670 J kg^-1 with a mean power of 0.19 W kg^-1 for the tandem system operating under the same parameters (SPA@SBAm). The energy recovery can be controlled, modulated and tuned by selecting both hydrogels with antipolyelectrolyte and polyelectrolyte effects and their performing parameters. This proof of concept provides blue energy harvesting by contributing both polyelectrolyte and antipolyelectrolyte effects in a single tandem setup; together with easy accessibility (diaper-based materials (SPA)) and known antibiofouling, these properties offer a robust alternative for energy harvesting.

Keywords: antipolyelectrolyte effect; energy recovery; hydrogel; polyelectrolyte effect; salinity gradient energy.

Abstract

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