Chemical functionality of surfaces for the characteristic adsorption of melamine

Abstract

The surface functionality leading to a high reversibility adsorption of melamine was determined. Four different silane coupling agents, namely, 3‐(tri‐methoxysilyl) propyl methacrylate (TMSPMA), n‐propyl tri‐methoxy‐silane (PTMS), 3‐(tri‐ethoxysilyl) propionitrile (TESPN), and tri‐methoxy‐(octadecyl) silane (OTMS) were taken for making chemical functionality methacrylate, short methyl, nitrile, and extended methyl group respectively. The adsorption behavior of melamine over the substrates with four functionalities was determined using quartz crystal microbalance (QCM). The adsorption kinetics and adsorption isotherms of the adsorption studies were analyzed. The initial adsorption rate depends on the hydrophobicity and roughness of the surfaces. However, the subsequent adsorption rate depends on the specific interaction. The data of equilibrium adsorbed mass at various equilibrium concentrations were fitted with the modified Brunauer–Emmett–Teller (BET) and Freundlich adsorption isotherms. The estimated model parameters were analyzed and compared with the reported parameters of the relevant systems. There is good agreement between our results and the reported results. In addition, very high adsorption with a very high binding constant was observed for the adsorption of melamine OTMS surface. On the other hand, high adsorption with an intermediate layer binding constant for the adsorption of melamine on the methacrylate surface was observed. Based on this, we propose using acrylate chemical functionality to develop molecularly imprinted polymer‐based melamine sensors.