The goal of this project is to develop complementary free radical polymerizatin techniques to prepare unkown classes of block copolymers derived from vinyl ester monomers and to study their phase behavior in the melt state and in dilute aqueous solutions. Melt phase behavior studies will exploit a complement of experimental methods including small-angle x-ray scattering, rheology, and electron microscopy (SEM and TME). Due to the bulk availability of binyl ester monomers, these block copolymers may enable the design of new soft materials having tunable rheological properties useful in commodity applications. The known biodegradability of some vinyl ester homopolymers also warrants invetigations into the potential biodegradability of these new block copolymers. These studies will elucidate relationships between polymer composition and architecture, morphologym and degradability for this new palette of monomers. The synthetic methods developed herein will be extended to enable the synthesis of well-defined, monodisperse poly(vinyl alcohol)-based amphiphilic block copolymers. As a consequence of the presence of strongly interacting hydroxyl groups in the hydrophilic corona block, these new polymeric surfactants are expected to exhibit different phase behaviors and rheological properties in dilute aqueous dispersions, as compared to those of other non-ionic surfactants. The strongly couple interplay of vinyl ester block copolymer synthesis and physical characterization in this research will shed light on the fundamental molecular parameters that underpin bulk materials properties. NON-TECHNICAL SUMMARY The major objective of this project is to explore the synthesis and properties of a new class of nanstructures plastics, which potentially will exhibit novel degradability and find use in both commodity and value-added applications. These studies will serve as the foundation for long-term efforts to develop biodegradable polymers as well as polymeric soaps that systematically modify the flow properties of fluids such as water. By virtue of their derivation from cheap chemical feedstocks, one anticipates that these materials may be economically produced n large scales for applications including drug delivery, degradable tissue scaffolds and other biomedical devices, stabalization of dispersions in personal care and pharmaceutical products, and surfactants for enhanced oil recovery that will help to increase overall yields. These research effots will be integrated into a wide spectrum of educational activites aimed at increasing scientific, social, and political awareness about the importance of commodity chemical innovations, with the aim of broadening participation of under-represented groups in science, technology, engineering, and mathematics (STEM) disciplines. Situated at the interface of chemistry, chemical engineering, and materials science, this research project will train both graduate and undergraduate students to tackle important challenges in polymer science. Research results will be integrated into undergraduate curricula through the development of experiments for a polymer lab course intended to foster interdisciplinary communication between STEM students. Additionally, curriculum materials for secondary and post-secondary educators highlighting the broader social and political impacts of commodity chemical innovations will be developed. These materials will serve as a prototype for inclusive curricula that employ interdisciplinary connections to cast scientific problems in captivating broader contexts, while highlighting past, present, and future research and development activities.
The development of inexpensive, degradable plastics and polymer surfactants ("soaps") that retain the versatile attributes of existing non-degradable, commodity materials is a major challenge for modern polymer science. Many well-studied degradable and sustainable materials cannot be produced on large scales at the low prices required for their widespread adoption. In order to address this challenge, we have developed the chemistry of petrochemically-derived vinyl ester monomers that may be enchained to form an array of degradable polymers at relatively low costs. Upon successfully synthesizing these materials and related block copolymers, we studied relationships between their solid-state structures at the nanometer length scale and their bulk physical properties, including their mechanical strength and toughness. We also studied the properties of water solutions of degradable poly(vinyl ester) block copolymer surfactants. Our studies suggest that these new classes of degradable plastics, elastomers, and polymer surfactants may have potential applications in enhanced oil recovery, drug delivery, and regenerative medicine. Intellectual Merit: We developed specialized polymer chemistries in order to produce previously unknown classes of degradable polymers. Through the strongly coupled interplay of polymer synthesis and physical polymer characterization, our research revealed new insights into the specific molecular attributes that govern the solid-state structures of these materials at the nanometer length scale, which in turn dictate their bulk physical properties. Findings of our detailed studies of these new degradable materials led to multiple peer-reviewed publications, as well as three composition of matter patent applications on poly(vinyl ester) copolymers focusing on their potential utility. Broader Impacts: We engaged in a wide range of educational and outreach activities with the following specific objectives: (1) enhancing interdisciplinary training at the undergraduate and graduate school levels, (2) broadening participation of traditionally under-represented groups in science careers, and (3) heightening awareness of the broader impacts of commodity polymers. The diverse group of high school, undergraduate, and graduate students involved in this research plan received highly interdisciplinary training at the interface of chemistry, chemical engineering, and materials science to enable them to address important research challenges in polymer science. The PI developed a new course in polymer chemistry with a clientele of over 100 students over the duration of this grant, and he helped to develop a new undergraduate laboratory course focusing on the physical characterization of polymeric materials. The PI also developed and implemented a series of curriculum materials in introductory college chemistry courses serving approximately 1000 students, which focused on the social, economic, and political impacts of commodity chemicals and polymeric materials on global sustainability and resource allocation.
