Adsorption and swelling studies of 2-hydroxyethyl methacrylate- and N,N-dimethylacrylamide-based porous copolymers and their possible applications for QCM-sensors

[Display omitted] •Dimethylacrylamide- and hydroxyethyl methacrylate copolymers were proposed for practical use as QCM-sensor membrane.•A correlation between the synthesis conditions and the copolymer morphology was found.•The microstructure (micro-granular and micro-porous) of the hydrogels was controlled.•HEMa-co-DMAa membranes show promise for sensing applications. An efficient one-vial method is described for the synthesis of porous frameworks from copolymers of 2-hydroxyethyl methacrylate with N,N-dimethylacrylamide in various monomers ratios. Characterization, swelling and sorption studies were performed for the materials obtained. A proof of concept for the use of porous membranes on QCM-type biosensors design was performed. Copolymerization between HEMA and DMAa was confirmed through ATR-FTIR and 1H NMR, while thermal analyses performed by TGA featured a dependence between the decomposition temperature and monomers ratio. Copolymers without cross-linker were unstable in water immersions, compromising their applicability. Thus, copolymer morphology was studied by adding a cross-linker agent (EGDMA). Swelling and sorption kinetics were evaluated by using two model molecules: methylene blue and lead (II) ions from aqueous solutions. We observed that swelling capacity is directly related to the cross-linking agent ratio, and DMAa content of the copolymer also. Finally, a copolymer with 50/50 mol%:HEMA/DMAa and 5 mol%:EGDMA (S4 copolymer) was selected as a covering membrane on the gold surface of a quartz crystal microbalance (QCM) to explore its potential as a material for the development of QCM-sensors. In conclusion, the copolymeric porous frameworks, based on N,N-dimethylacrylamide- and 2-hydroxyethyl methacrylate, are suitable for remediation and adsorption applications, including the support recognition probes in biosensors.