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(a). 200 nm. Role of Non-Equilibrium Pinned Layers on the Thermodynamics of Confined Polymer Blends – Sanat K. Kumar (Rensselaer Polytechnic) DMR 0413755.
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(a) 200 nm Role of Non-Equilibrium Pinned Layers on the Thermodynamics ofConfined Polymer Blends – Sanat K. Kumar (Rensselaer Polytechnic) DMR 0413755 Polymers are very flexible materials which are used widely. However, they are little used in structural applications due to their low modulus. Recent work has shown that the mechanical behavior of these materials can be favorably altered by the addition of trace amounts of a nanofiller. However, the resulting changes in polymer properties are poorly understood, primarily due to the non-uniform spatial distribution of nanoparticles. We show that the thermomechanical properties of “polymer nanocomposites” are quantitatively equivalent to the well-documented case of planar polymer films. We quantify this equivalence by drawing a direct analogy between film thickness and an appropriate experimental interparticle spacing, thus allowing us to use the vast body of literature in the area of thin films to design improved composites. In addition to this important pratical connotation, our results also offer new insights into the role of confinement on the glass transition. (b) Tg h (nm) (a) TEM slice from a 15weight% SiO2/polystyrene composite.Note the strong aggregation of particles. (b) Comparison between glass transition response of PS nanocomposite and thin PS films, plots of glass transition shift vs. film thickness. Data from literature on thin films are shown as open circles. Filled circles are data from nanocomposites for two different molecular weights. Nature Materials, in press.
Role of Non-Equilibrium Pinned Layers on the Thermodynamics of Confined Polymer Blends – Sanat K. Kumar (Rensselaer Polytechnic)DMR 0413755 Education This grant supports a graduate student pursuing his Ph.D. degree Yuping Xie (2nd year) and one post-doctoral fellow Sudeepto Sen. An undergraduate student (Misha Verma, pictured below) and a high school student (Kayla Richardson) have also been supported as part of this grant. Outreach Taught a course on “Nanomaterials” to undergraduate students at RPI Participate in the programs to involve high school students in research programs. Employed two undergraduate women in experimental research. Participate in the development of modules to be employed in the “Molecularium”, a planetarium based set of animated movies designed to expose K-6 students to the world of science.