The objective of the proposed research program is to understand the implications of homopolymer and electrolyte additives on the texture formation in block copolymer materials, and to establish the effect of filler particle shape on texture formation in block copolymer/nanoparticle blends. Specifically, this program will address the following questions: (1) What is the significance of enthalpic interactions on the grain boundary segregation process of homopolymer fillers and how does enthalpic interaction affect the capacity of a filler component to stabilize grain boundary structures? (2) To what extent does the effect of filler species on the grain boundary formation process obey universal principles? (3) Is it possible to selectively stabilize particular grain boundary structures by addition of filler particles that exhibit defect geometry-matched crystal shapes and what is the implication of grain boundary discrimination on the texture evolution of block copolymer/nanoparticle blends? Ultimately, this program aims to contribute to the knowledge-base that will be critical for the future rational design of block copolymer nanocomposite materials with tailored properties that are relevant to a host of transformative technology applications ranging from microfabrication or optical coatings to materials for energy storage and conversion. The proposed research will involve experimental and characterization techniques that are complementary to existing techniques at Carnegie Mellon University and that will be beneficial to the wider polymer community in the Pittsburgh area.
NON-TECHNICAL
The aim of this proposal is to understand the governing parameters that control structure formation in block copolymer-hybrid materials. These are materials that are capable of the self-organization into a hierarchy of functional nanostructures that are of technological relevance in applications ranging from polymer membranes for next-generation lithium ion batteries to high-performance polymer photovoltaic materials. The particular goal of this project is to develop processes to control the formation of defects in these nanostructures, a key requirement for the future technological exploitation of block copolymer hybrid materials. The program will enhance the teaching of two polymer classes and provide training for one graduate and several undergraduate researchers in the critical area of polymer and nanoscale materials. Ongoing collaborations with researchers at Florida A&M University will be leveraged to enhance participation of minority students within the program. By virtue of guest lectures and demonstrations on the particular topic of ?Nanostructured Materials? this project will furthermore aim to stimulate students of middle and high schools in the East Liberty School district of Pittsburgh to pursue higher education in STEM related areas.
Because of their ability to organize into periodic microdomain morphologies, block copolymer (BCP)-based materials have become one of the most vibrant research areas in the field of polymer science. The combination of structural regularity on the nanometer lengthscale in combination with the wide range of chemical functionalities as well as the excellent processibility have inspired applications of BCP materials in advanced technology areas ranging from optical sensors to high-power density materials for energy storage or photovoltaics to biomedical engineering. To harness the unique properties of BCPs the control of the materials organization from the nano-to macroscopic lengthscale is an essential prerequisite. The overall objective of the present work was to establish the experimental tools to facilitate understanding of the governing parameters that control defect formation in BCP materials and to elucidate the role of impurities on structure evolution. The two primary contributions of this study entail (1) the establishment of a novel technique to measure the energy of defects in BCP and (2) the demonstration that minor amounts of impurities result in significantly increased defect densities. These results lend themselves to the advancement of process conditions to faciliate more perfect material strucutres with improved electronic or optical properties. The grant has supported the work of two graduate and two undergraduate students. One undergraduate researcher has received a prestigious fellowship to support a one-year visit to the Max-Planck Institute of Polymer Research in Germany prior to pursuing higher studies in the US. The grant has furthermore enabled the collaboration of the PI with a middle and high school teacher at The Ellis School – an all-girls school in the Pittsburgh area - to develop a short module on ‘Materials Science and Engineering’. This module is being offered to students at the junior high school level during the last two weeks of classes in order to raise the students’ interest (and understanding) of engineering disciplines and Materials Science and Engineering in particular.
