Polymeric cantilever sensors functionalized with multiamine supramolecular hydrogel

This paper presents a multiamine supramolecular hydrogel (SH) modified SU-8 cantilever sensor. A chemical process to integrate the SH on the surface of SU-8 cantilever is developed to improve the stability and reusability of the functionalized cantilever sensor, instead of physical surface functionalization methods such as direct coating and self-assembly. The network structure of the SH is formed through a ring-opening and amine-substituted reaction in epoxy groups of the SU-8. The surface functionalization of the SU-8 cantilever is characterized by using scanning electron microscopy (SEM) and X-ray photoelectron spectroscopy (XPS). The modified SU-8 cantilever sensor has been successfully applied for real-time measurement of metal ions concentration in aqueous solutions. Responses from the cantilever due to surface stress are induced by the axial coordination of ferric ions to amino groups of the SH and the chemical energy is converted into the mechanical energy which can be measured by a piezoresistive sensor. The concentration-dependent performance of the sensor is demonstrated and discussed, indicating a potential use of SH functionalized cantilever sensors.