Interaction between Volatile Organic Compounds and Functional Monomers in Molecularly Imprinted Materials

Molecularly imprinted polymers (MIPs) have been playing an increasingly important role in volatile organic compounds (VOC) sensing for air quality control. The unique feature of these materials is their biomimetic molecular recognition functionality. Theoretical chemistry can advance our ability to design and synthesize new MIPs with specific functions, providing valuable insight into the system at the atomistic level, and therefore are able to explain microscopic behavior. In this work, we have studied the interaction of pyridine, as a recognition element, with methacrylic acid as the functional monomer, in a pre-polymerization step in the formation of a specific molecularly imprinted polymer. Quantum chemistry calculations were performed at the M052X/6-311++g(d,p) level. The binding characteristics of the imprinted polymer were examinated in detail. Ethylene glycol dimethacrylate is proposed as the cross-linker, and chloroform as the solvent. In addition, we investigate adsorption of toluene and benzene in the MIP structure. The aim is to test whether the model is able to recognize pyridine among these similar species and to explore the theoretical sensitivity range of these materials towards pyridine and other VOCs. Another test of the model is its ability to exhibit preferential adsorption of toluene over benzene, as has been observed experimentally in similar systems. The performed quantum chemistry calculations reproduce the preferential adsorption of pyridine over toluene and benzene, as well as the preferential adsorption of toluene over benzene.