Water is a Poor Solvent for Densely Grafted Poly(ethylene oxide) Chains You-Yeon Won, Purdue University, DMR 0906567.
Poly(ethylene oxide) (PEO) brushes are widely used for surface modification of biomaterials. In order to investigate how the high spatial confinement that the PEO chains experience in a polymer brush situation influences the way the polymer chains interact with water molecules, a model PEO brush system, prepared by spreading a PEO–PnBA diblock copolymer onto an air–water interface, was investigated by using the neutron and X-ray reflectivity techniques. We found that contrary to what is commonly observed for PEO in normal situations, the PEO chains are actually not “hydrophilic” when they exist as polymer brush chains [J Phys Chem B 116, 7367 (2012)]. It was also discovered that inside of the PEO brush, the water density is significantly lower than that of bulk water, in particular, in the region close to the PnBA–water interface [J Phys Chem Lett 3, 1589 (2012)].
In Spring 2012, Won and his students have participated in the Purdue NanoDays event, which is an annual outreach event held every year in April showcasing the University’s nanoscience research activities to local educators, K-12 students, community members, our own Purdue employees and their families. Starting in Summer 2012, Won Laboratory has also been participating in a Summer High School Research Experience Program. This Program has been set up, by a partnership between a local high school (West Lafayette High School, West Lafayette, Indiana) and
Purdue University, to provide a summer opportunity for talented/motivated high school students to gain research experience with Purdue Professors. Through this Program, a high school junior (Chris Zhang) is currently involved in a project that investigates the mechanism by which polymer/DNA nanoparticles, a formulation commonly used in clinical trials for gene therapy treatments, are able to interact with cell membranes in the body. Under the guidance of Won, this student is currently working toward participating in the Indiana State Science Fair Competition in 2013.