There has been continuing interest in polymer nanocomposites, which are mixtures of polymeric materials and nanometer-sized inorganic particles, primarily because they offer the promise of significantly improved physical properties relative to the corresponding pure polymer. While there have been many studies on these topics to date, very few have gone from the scientific details relevant to controlling the nanoparticle (NP) dispersions to optimizing the practically relevant thermal and mechanical properties that emerge. Each of the three prongs of this research project focuses on establishing this connection in a way that has a direct impact on applications. (i) The proposed research on pressure effects will delineate the role of processing in homogenizing polymer/NP mixtures and the consequences of this changing dispersion state on properties. (ii) In a second thread, this research will study the role of NP shape on optimizing thermal and mechanical properties. (iii) Finally, the practical consequences of the proposed research will be explored by replacing chemically attached polymer molecules on the NPs by the physically attached ones. Are these strategies equivalent, and, if not, in what tangible ways are they different?
These research efforts will be coupled to a suite of education and outreach activities. Driven by the group's recent activities involving recruiting high school and undergraduate students for summer research, the proposal is to continue to recruit students from historically minority schools (such as Florida A&M), as well as undergraduate and high school students (and teachers) from the greater New York City environment. The PI's group has previously worked with several women and minority high-school students who have subsequently gone on to study science and engineering in college, and will continue this pipeline approach toward science and engineering careers.
There has been continuing interest in polymer nanocomposites, primarily because these hybrids offer the promise of significant property improvements relative to the pure polymer. While there have been many studies on this topic to date, very few of them have gone all the way from controlling the nanoparticle (NP) dispersion state to optimizing the thermomechanical properties that emerge. The overall approach proposed, which combines experiments and theory, focuses precisely on bridging this gap by (a) studying the fundamentals of the assembly process and its consequences on properties, and (b) porting the evolving understanding to make it more amenable to applications. The proposed research has the following three prongs: (i) Critically studying the role of pressure in homogenizing polymer/NP mixtures. Can high pressure be used to control NP dispersion and what are its effects on properties? (ii) Similarly, the research will explore the role of NP shape as a route to further optimizing thermomechanical properties. (iii) Finally, the practical consequences of the proposed research will be studied by replacing chemically-grafted chains on the NPs by the physical adsorption of chains. Is this idea feasible and what are its advantages and disadvantages in terms of property improvements?
These research activities are coupled to extensive education and outreach activities. Driven by the group's recent activities involving high school and undergraduate students for summer research, and with the group's well-developed interactions with Florida A&M University (an HBCU), the proposal is to continue to recruit underrepresented students (both women and minorities) at the high school, undergraduate and graduate levels to be part of the group's research efforts. The PI is also working with the Chemical Engineering department at the City College of New York to bring together academics in the Greater New York area (faculty and students), local industry and national laboratories in an annual chemical engineering symposium. The goal is, not only to place graduating students into local industry, but also to attract industrial participants into higher degree and/or refresher programs at Columbia.
