Facile synthesis of poly(DMC-co-HPA) hydrogels via infrared laser ignited frontal polymerization and their adsorption-desorption switching performance

In this work, we report a versatile infrared laser ignited frontal polymerization technique for the fabrication of a series of poly(DMC-co-HPA) hydrogels (DMC = methacryloxyethyltrimethyl ammonium chloride, HPA = hydroxypropyl acrylate). Because the method is based on the exothermic reaction, no further energy is required in the reaction once it is initiated. Moreover, we have found the polymerization process is a pure frontal polymerization model without involving any other reaction process. The dependence of frontal velocity and temperature on the reaction time is thoroughly discussed. The as-prepared hydrogels are pH-responsive and their maximum equilibrium swelling ratio could reach ∼;3,890%. Also, the as-prepared poly(DMC-co-HPA) hydrogels capable of adsorption/desorption switching performance can be utilized for heavy metal ion removal in wastewater treatments. Interestingly, the hydrogels can float on the water surface after intaking heavy metal ions by the combination of kerosene and polyoxyethylene sorbitan monolaurate (Tween 20) in hydrogel components, greatly enhancing treatment efficiency. We believe the method described herein to rapidly construct functional hydrogels with the ability to remove heavy metal ions may find unique applications in emergency processing of water pollution.