Influence of cross-linkers' amount on the performance of the piezoelectric sensor modified with molecularly imprinted polymers

In this paper, the performance of the piezoelectric sensor modified with the molecularly imprinted polymers (MIPs), which were synthesized in the presence of different amount of cross-linker (ethylene glycol dimethacrylate, EDMA) and constant amount of functional monomer (methacrylic acid, MAA) and template (niacinamide) has been investigated detailedly. The morphology of these polymers was analyzed by using scanning electron microscopy (SEM) and the results show that, to get optimal uniformly size, the optimum molar ratio range of EDMA to MAA is 5:1-10:1. The affinity was estimated by using Scatchard analysis. Results show that the dissociation constant (KD) and the apparent maximum number of affinity-binding sites (Qmax) increase with the increment of the ratio of EDMA to MAA until the ratio reaches 20. The response performance of these sensors was investigated. The selectivity of the MIP-sensors decreased with the decrease of the ratio of cross-linking in the polymers. In the range of 5 × 10−9 to 5 × 10−6 M, the frequency response of the MIP-sensors increase with the increment of the molar ratio of EDMA to MAA until the ratio reaches 20.