The proposed research on "Regulation of Polymer Blend Morphology Using Nanospheres and Nanorods, "aims to understand how phase separation in polymer blend films affects the dispersion of nanoparticles (NP) and how NP affect phase evolution, wetting and film stability. Whereas prior studies focus on neat blends, the current study will investigate how particle characteristics, in particular, surface chemistry and shape, influence how NP disperse and organize in a multi-phase morphology. Nanospheres of silica and nanorods of CdSe will be investigated. To control their location, NP are functionalized by acid-groups, neutral brushes, and attractive brushes. By tuning the surface properties, which control partitioning and organization, NP can be driven into one domain or towards the interface between phases. The location of NP dictates film characteristics including wetting layer growth rate, mprphology, phase evolution, and film stability. By controlling the location of NP, a new route for engineering phase size is expected from these systematic studies. For example, stable biocontinuous structures can be produced by NP "jamming" resulting in highly efficient photovoltaic devices. The proposed research requires a palette of complementary depth and lateral profiling techniques including ion beam etching combined with scanning electron microscopy.
NON-TECHNICAL SUMMARY:
Polymer nanocomposites (PNC) are foundin everyday materials such as tires and golfballs as well as high technology devices for energy conversion and sensor applications. PNC are examples of nano-based materials, which are driving the revolution in nanotechnology. This exploding field has received worldwide investments totaling $8 billion in 2004 with an anticipated impact of $2.6 trillion by 2014. Although highly versatile and widely used, a fundamental understanding of PNC is lacking and basic science is necessary to produce PNC based devises that are reliable, efficient and economical.
During the past 3.5 years, this NSF project has provided research training for 25 engineering undergraduates (10 females) and 6 high school teaching (2 female, 2 minority). Two of these have received NSF Graduate Fellowships. Lectures about polymer science to teachers in the Philadelphia School District has lead to great enthusiasm about developing laboratories for a Science Van that will reach out to underrepresented nimorites in middle school. With University encouragement, the Science Van project is in the planning stages. International collaborations with scientists from the United Kingdom and the Czech Republic will provide students with a better understanding about research in these countries.
