Controllable thermal and pH responsive behavior of PEG based hydrogels and applications for dye adsorption and release

A series of controllable thermal and pH dual-responsive copolymeric hydrogels (PMA) were prepared by a one-pot reaction with poly(ethylene glycol) methyl ether acrylate (PEGA), 2-methoxyethyl acrylate (MEA) and acroleic acid (AA). The hydrogels exhibited good mechanical properties and a sensitive response to pH and temperature. Besides, the Lower Critical Solution Temperature (LCST) of the hydrogels can be adjusted from 37 °C to 58 °C by changing the content of AA. The hydrogels also showed excellent selective adsorption properties. The maximum adsorption quantity of organic cationic dye brilliant green and methylene blue were 0.49 mg mg^-1 and 0.42 mg mg^-1 respectively, much better than previous reports. Furthermore, using the thermal and pH responsibility, the PMA hydrogels can release the adsorbed molecules with control. Nearly 95% of carriers could be released at pH 4.01 and 65 °C over 8 h. The regeneration ability makes the materials easy to reuse many times. Due to these properties, these dual-responsive hydrogels have great potential applications in various fields for adsorption, drug delivery, release and tissue engineering.