Hydrogels are widely studied for chemical sensors. However, they are known to adsorb organic compound and metal ions. The adsorption abilities of hydrogels against organic compounds and metal ions will negatively affect the performance of a hydrogel based chemical sensor. To clarify the effect of hydrophobic pollution on swelling behavior of temperature-sensitive gel, the temperature-responses of spherical N,N-diethylacrylamide (DEAA) gel in phenol solution were evaluated using the collective polymer diffusion constant. Phenol was selected as a model hydrophobic pollution. The equilibrium radius of DEAA gel changed discontinuously at about 874 g/m 3 phenol solution, and the collective polymer diffusion constant decreased sharply between 874 and 916 g/m 3, suggesting a “critical slowing down”. The phenol concentration difference EC was successfully used to correlate phenol concentration with the collective polymer diffusion constant. The correlation will be useful as an estimation of hydrogel response reduction associated with hydrophobic pollution.
References
[1]
Shin, J.; Braun, P.V.; Lee, W. Fast response photonic crystal pH sensor based on templated photo-polymerized hydrogel inverse opal. Sens. Actuators B 2010, 150, 183–190, doi:10.1016/j.snb.2010.07.018.
[2]
Lee, S.; Ibey, B.L.; Coté, G.L.; Pishko, M.V. Measurement of pH and dissolved oxygen within cell culture media using a hydrogel microarray sensor. Sens. Actuators B 2008, 128, 388–398, doi:10.1016/j.snb.2007.06.027.
[3]
Pi, S.; Ju, X.; Wu, H.; Xie, R.; Chu, L. Smart responsive microcapsules capable of recognizing heavy metal ions. J. Colloid Interface Sci. 2010, 349, 512–518, doi:10.1016/j.jcis.2010.05.084.
[4]
Herber, S.; Olthuis, W.; Bergveld, P. A swelling hydrogel-based PCO2 sensor. Sens. Actuators B 2003, 91, 378–382, doi:10.1016/S0925-4005(03)00121-7.
[5]
Meskath, S.; Urban, G.; Heinzea, J. A new optochemical chlorine gas sensor based on the application of amphiphilic co-networks as matrices. Sens. Actuators B 2011, 151, 327–332, doi:10.1016/j.snb.2010.07.028.
Endo, T.; Yanagida, Y.; Hatsuzawa, T. Colorimetric detection of volatile organic compounds using a colloidal crystal-based chemical sensor for environmental applications. Sens. Actuators B 2007, 125, 589–595, doi:10.1016/j.snb.2007.03.003.
[8]
Yamagiwa, K.; Komi, T.; Kumakura, A.; Yokoyama, S.; Yoshida, M.; Ohkawa, A. Photo-crosslinked copolymer gel as an adsorbent for temperature-swing adsorption process. J. Chem. Eng. Jpn. 2004, 37, 1274–1278, doi:10.1252/jcej.37.1274.
[9]
Yamagiwa, K.; Komi, T.; Yoshida, M.; Ohkawa, A.; Iida, T. Temperature-swing adsorption of nonionic surfactant with photo-crosslinked polymeric gel. J. Chem. Eng. Jpn. 2001, 34, 1171–1176, doi:10.1252/jcej.34.1171.
[10]
Tokuyama, H.; Yanagawa, K.; Sakohara, S. Temperature swing adsorption of heavy metals on novel phosphate-type adsorbents using thermosensitive gels and/or polymers. Sep. Purif. Technol. 2006, 50, 8–14, doi:10.1016/j.seppur.2005.11.001.
[11]
Tokuyama, H.; Kanehara, A. Temperature swing adsorption of gold(III) ions on poly(N-isopropylacrylamide) gel. React. Funct. Polym. 2007, 67, 136–143, doi:10.1016/j.reactfunctpolym.2006.10.006.
[12]
Takeshita, K.; Matsumura, T.; Nakao, Y. Separation of americium(III) and europium(III) by thermal-swing extraction using thermosensitive polymer gel. Prog. Nucl. Energy 2008, 50, 466–469, doi:10.1016/j.pnucene.2007.11.085.
[13]
Huber, D.L.; Manginell, R.P.; Samara, M.A.; Kim, B.; Bunker, B.C. Programmed adsorption and release of proteins in a microfluidic device. Science 2003, 301, 352–354, doi:10.1126/science.1080759.
[14]
Klouda, L.; Mikos, A.G. Thermoresponsive hydrogels in biomedical applications. Eur. J. Pharm. Biopharm. 2008, 68, 34–45, doi:10.1016/j.ejpb.2007.02.025.
[15]
Sershen, S.; West, J. Implantable, polymeric systems for modulated drug delivery. Adv. Drug Deliv. Rev. 2002, 54, 1225–1235, doi:10.1016/S0169-409X(02)00090-X.
[16]
Tokuyama, H.; Kanazawa, R.; Sakohara, S. Equilibrium and kinetics for temperature swing adsorption of a target metal on molecular imprinted thermosensitive gel adsorbents. Sep. Purif. Technol. 2005, 44, 152–159, doi:10.1016/j.seppur.2005.01.004.
[17]
Tanaka, T.; Fillmore, J. Kinetics of swelling of gels. J. Chem. Phys. 1979, 70, 1214–1218, doi:10.1063/1.437602.
[18]
Li, Y.; Tanaka, T. Kinetics of swelling and shrinking of gels. J. Chem. Phys. 1990, 92, 1365–1371, doi:10.1063/1.458148.
[19]
Sato Matsuo, E.; Tanaka, T. Kinetics of discontinuous volume-phase transition of gels. J. Chem. Phys. 1988, 89, 1695–1703, doi:10.1063/1.455115.
[20]
Kosik, K.; Wilk, E.; Geissler, E.; Laszlo, K. Interaction of phenols with thermo-responsive hydrogels. Colloids Surf. A Physicochem. Eng. Aspects 2008, 319, 159–164, doi:10.1016/j.colsurfa.2007.07.022.
[21]
Tajima, H.; Yoshida, Y.; Yamagiwa, K. Experimental study of swelling and shrinking kinetics of spherical poly (N,N-diethylacrylamide) gel with continuous phase transition. Polymer 2011, 52, 732–738, doi:10.1016/j.polymer.2010.12.029.
[22]
Tajima, H.; Yoshida, Y.; Abiko, S.; Yamagiwa, K. Size adjustment of spherical temperature-sensitive hydrogel beads by liquid–liquid dispersion using a Kenics static mixer. Chem. Eng. J. 2010, 156, 479–486, doi:10.1016/j.cej.2009.11.010.
Kawashima, T.; Koga, S.; Annaka, M.; Sasaki, S. Roles of hydrophobic interaction in a volume transition of alkylacrylamide gel induced by the hydrogen-bond-driving alkylphenol binding. J. Phys. Chem. B 2005, 109, 1055–1062, doi:10.1021/jp046236x.
[25]
Koga, S.; Kawashima, T.; Sasaki, S. Elastic relaxation of collapsed poly(alkylacrylamide) gels and their complexes with phenol. J. Phys. Chem. B 2004, 108, 10838–10844, doi:10.1021/jp049452e.
[26]
Suzuki, Y.; Suzuki, N.; Takasu, Y.; Nishio, I. A study on the structure of water in an aqueous solution by the solvent effect on a volume phase transition of N-isopropylacrylamide gel and low-frequency Raman spectropy. J. Chem. Phys. 1997, 107, 5890–5897, doi:10.1063/1.474314.
[27]
Laszio, K.; Kosik, K.; Rochas, C.; Geissler, E. Phase transition in Poly (N-isopropylacrylamide) hydrogels induced by phenols. Macromolecules 2003, 36, 7771–7776, doi:10.1021/ma034531u.
[28]
Kosik, K.; Geissler, E.; Zrinyi, M.; Laszlo, K. Interaction of non-ionic hydrogels with small aromatic molecules. Polym. Adv. Technol. 2003, 14, 771–775, doi:10.1002/pat.393.
[29]
Takahashi, K.; Takigawa, T.; Masuda, T. Swelling and deswelling kinetics of poly(N-isopropylacrylamide) gels. J. Chem. Phys. 2004, 120, 2972–2979, doi:10.1063/1.1636695.
[30]
Tokita, M.; Tanaka, T. Reversible decrease of gel-solvemt friction. Science 1991, 253, 1121–1123, doi:10.1126/science.253.5024.1121.
