Direct Synthesis of Monodisperse Hollow Molecularly Imprinted Polymers Based on Unfunctionalized SiO₂ for the Recognition of Bisphenol A

A novel and effective approach was developed to synthesize monodisperse hollow molecularly imprinted polymers (MHMIPs) with unfunctionalized SiO₂ spheres in a mixture of toluene and CH₃CN.The factors that affected the synthesis of MHMIPs were systematically investigated.It was determined that a suitable ratio of toluene to CH₃CN and the use of a functional monomer that can generate double H-bonding interactions were the critical factors to obtain MHMIPs with high uniformity and monodispersion.The obtained MHMIPs exhibited a fast adsorption rate and high adsorption capacity (270 μmol/g) for bisphenol A.As the shell thickness increased from 90 nm to 130 nm, the binding capacity of the imprinted shells decreased gradually.The relative selectivity coefficients of MHMIPs for tetra-bromobisphenol A (TBBPA), phenol and p-tert-butylphenol (PTBP) were calculated as 1.53, 1.83 and 1.90, respectively.These findings indicate that MHMIPs have good adsorption performances and suggest applications in the selective removal or sensitive analysis of bisphenol A.