Recognition ability of temperature responsive molecularly imprinted polymer hydrogels

Abstract

Temperature responsive imprinted polymer hydrogels were synthesized and characterized, which recognize target molecule, 4-amino pyridine (Apy), via electrostatic interaction and hydrogen bonding. The interaction between Apy and functional monomer methacrylic acid (MAA) was investigated by FTIR and ¹H-NMR. Adsorption and release of Apy were determined at 60 °C and 20 °C, respectively. The amount of adsorption of Apy in the imprinted hydrogels was 2–3 times higher than that in the non-imprinted hydrogels. At 20 °C, 82% of Apy is released by the imprinted hydrogels, but only 60% by the non-imprinted hydrogels. The unique aspect of these imprinted polymer hydrogels is that they combine molecular recognition with thermo-responsiveness; reversible recognition and release of target molecule are realized by changing temperature. Selective recognition tests of the imprinted polymer hydrogels were carried out using three compounds structurally related to Apy, pyridine, 4-methylpyridine and 2-aminopyridine. The imprinted hydrogels exhibited the highest selectivity for Apy, while the non-imprinted hydrogels showed similarly low adsorption for all the substrates. As the imprinted polymer hydrogels have good temperature response, selectivity and reusability, they have great potential for application in separation field and in drug controlled release systems.