Semi Fluorinated Polymers: Forming Energy Controlled Responsive Interfaces

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TECHNICAL ABSTRACT The proposal seeks to explore the potential of semifluorinated polymers as responsive self healing interfaces. Responsive interfaces are ubiquitous in biological manifolds. From self cleaning surfaces and adhesion controlled interfaces to self healing layers, nature has inspired intensive efforts to design synthetic responsive polymeric interfaces. Fluorinated and protonated segments are highly immiscible and exhibit very different surface interactions. As a result, inserting a short fluorinated segment into a polymer chain is often sufficient to induce micro-phase separation as well as long range order. Tailoring highly incompatible short segments into one chain offers a means to obtain interfaces that can locally rearrange and respond to changes in the environment while retaining the integrity of the layers. The driving forces for reversible responses lie in the tendency of any system to achieve thermodynamic equilibrium. To attain this goal, the research will identify and quantify when feasible, the factors that control the structure and interfacial characteristics of thin semifluorinated films, study the dynamics of solvents at these complex interfaces and identify the conditions under which they form interfaces that respond to stimuli. The proposed study will focus on three groups of semifluorinated copolymers: a) hydrocarbons and fluorinated aliphatic chains, b) random co-polymer bridged by perfluoro cyclobutane, and c) diblock copolymers of polystyrene and semifluorinated siloxane blocks. The structure and energies of the interfaces will be studied by microscopy and scattering techniques accompanied by molecular dynamic computer simulations. These measurements, in comparison with the bulk structure and dynamics will provide a multiple length scale picture critical for effective design of responsive interfaces.NON TECHNICAL SUMMARYThe proposed research will impact the development of new technologies and contribute to science education. Developing responsive polymeric materials with controlled optical and conducting characteristics together with selective adhesion is essential for the design of next generation devices from nano-bio sensors and implants to plastic electronics and self healing coatings. The results of the proposed research will directly impact technological advancements. Ongoing collaboration of the PI with scientists at 3M will serve as a jump start for technological implementation and testing of the findings. Further applications of transport will be explored via small business initiatives at Clemson. With the realization of the significance of to science education at early stages, the proposed research will incorporate projects designed for high school students and derive ways to disseminate science highlights to the public. This will be done together with two high school teachers in Greenville SC, David Dollbey from Riverside High School and Dr. Wisenhunt from Greenville High School.On the graduate level, the project will incorporate studies at Clemson University and in national laboratories, using neutron and X-ray sources. The traditional graduate education will transcend to training the next generation of material researches to take advantage of the unique information extracted from neutron and X-ray techniques to the design of new materials. This is particularly significance in a state where the use of these techniques has been very limited. The PI is the first scientist from her University to use some of these resources. This initiative will foster new collaborations between Clemson scientists and those in national laboratories. This educational initiative in of further significance in view of recent developments in experimental neutron techniques, funded partially by the National Science Foundation, that allow probing the response of new materials.