Graphene oxide as a sacrificial material for fabricating molecularly imprinted polymers via Pickering emulsion polymerization

Abstract

Graphene oxide (GO) was introduced as a sacrificial material, for the first time, to fabricate a hollow molecularly imprinted polymer (HMIP) via Pickering emulsion polymerization. A stable oil-in-water Pickering emulsion was obtained, and the optimum pH values affecting the stability of the emulsion were investigated. After polymerization, GO was peeled off using ammonia solution (pH = 11) via ultrasonication, and substantial specific binding sites were exposed. The physical and chemical properties of the material were characterized and analyzed by scanning electron microscopy, Fourier transform infrared spectroscopy, and thermogravimetric analysis. The equilibrium adsorption could be reached rapidly within 5 min, showing excellent adsorption efficiency, and the equilibrium adsorption capacity was 40.76 mg g⁻¹ at 25 °C. The imprinting factor was about 2.62. The selective analysis indicated a high affinity and selectivity of HMIP toward template diclofenac over mefenamic acid and carbamazepine.