Supplementary Materials: Surface Molecularly Imprinted Polymer Film with Poly(p-aminothiophenol) Outer Layer Coated on Gold Nanoparticles Inner Layer for Highly Sensitive and Selective Sensing Paraoxon

The nucleation potential and deposition time was used to control the size and the amount of the deposited AuNPs, respectively, for obtaining an optimum coverage of AuNPs on the electrode surface. The effect of deposition potential on particle size and density for a constant charge passed (6 × 10−4 C) has been investigated. It is clear from the images (see Figure S1) that the size of the AuNPs decreased and the density of the Au NPs increased with decreasing electrode potential from 0.2 to −0.4 V vs. Ag/AgCl while keeping the total coverage in terms of Au atoms constant on the surface by controlling the amount of charge deposited. It may be due to the low overpotential (0.2 V) resulted in a lower density of nucleation sites and leaded to large and sparsely dispersed AuNPs [1]. While the higher overpotentials (0.0 and −0.2V) are energetically favorable the formation of larger numbers of nucleation sites all over the electrode surface, hence resulted in the smaller and densely dispersed AuNPs. However, we can clear see that small agglomeration of AuNPs occurred when a high deposited overpotential (−0.4 V) was used, which may due to the increased amount of nucleation sites as well as high grow rates of AuNPs. Therefore −0.2 V vs. Ag/AgCl was selected as the optimal potential for AuNPs deposition.