Synthesis of novel photoresponsive molecularly imprinted polymer microspheres with special binding properties

An azobenzene-containing molecularly imprinting polymer microsphere with photoresponsive binding properties toward 2,4-dichlorophenoxyacetic acid (2,4-D) was successful prepared via silica surface polymerization. The number-average diameters of silica and imprinting polymer microsphere are 0.5 and 0.7 lm, respectively. The static adsorption, binding and selectivity experiments were performed to investigate the adsorption properties and recognition characteristics of the polymers for 2,4-D. The equilibrium adsorptive experiments indicated that 2,4-D-SMIP(surface molecularly imprinted polymers) has significantly higher adsorption capacity for 2,4-D than its nonimprinted polymers (SNIP). The binding constant Kd and apparent maximum number Qmax of the imprinted polymer were determined by Scatchard analysis as 0.054 mmol L-1 and 0.167 mmol g(-1), respectively. The result of photoregulated release and uptake of 2,4-D experiment demonstrated that azo-containing SMIP can make use of light and change it into mechanical properties to release and take up the template molecules. It means that the SMIP can be controlled by light. (C) 2013 Wiley Periodicals, Inc.