Supramolecularly Crosslinked Microgels for Heavy Metal Sensor Fabrication

Stimuli-responsive polymers are composed of monomeric building blocks with chemical functionality that allows them to change physically and/or chemically in response to the conditions of their environment. Exploiting the fact that the physical and/or chemical properties of the stimuli-responsive polymers can be tailored, the Serpe Group conducts research to develop unique optical materials for sensing, triggered/controlled drug delivery systems, and novel water remediation systems (among other things). Our polymer of choice is frequently poly (N-isopropylacrylamide) (pNIPAm), which is a water-soluble polymer that responds to changes in temperature by changing its conformational state. In previous research with the group of Prof. Xi Zhang at Tsinghua University we have been able to show that supramolecularly crosslinked pNIPAm-based microgels could be generated from supramonomers. Interestingly, we were able to demonstrate that the microgel supramolecular crosslinks could be designed to "break" in the presence of specific small molecules; when the crosslinks break, the microgels were shown to change size, which can be detected using various techniques. As part of the current project, we will generate supramolecular microgels that change their size in the presence of harmful heavy metal ions (e.g., Hg, Pb, etc). Once the supramolecular microgels are generated, they will be characterized, and then incorporated into sensor devices that the Serpe Group has pioneered since 2009. The result of the research will be an inexpensive, easy to use heavy metal ion sensing technology that capitalizes on the expertise and knowhow of both groups. By quantifying the amount of heavy metals in water samples in real time,industry and government will be able to control heavy metal ion release to the environment and allow those responsible for the release to respond quickly to any unacceptable heavy metal ion releases to the environment. Furthermore, once the technology has been proven, it can be easily modified to detect other small molecules in water, including any organic contaminants.