Polycarbodiimide are helical polymers which show chiroptical switching properties. This is mainly due to the contraction and expansion of the helical conformation in both the solid and solution state. We have studied how these play an important role in the behavior of these polymers. All switching polymers studied thus far have had straight alkane side chains. In this work, we modified the structure of the polycarbodiimides by introducing new alkyne functional group, hexynyl-5-phenylcarbodiimide. We were then able to introduce branching and steric alkyl groups to the side chains by using the click addition reaction. To change the solid-state chain-chain packing of this polymer, hexynyl-5-phenylcarbodiimide was also copolymerized with phenyloctadecylcarbodiimide and the switching properties of these copolymers were studied. Results provided the solution state reversible switching between 2 distinct conformations (state A and state B) observed at different temperatures using infrared spectroscopy (IR). Sensing of volatile organic chemicals (VOC) have also been studied using IR which allowed distinguishing certain hydrocarbons and different polar solvents. Reported here, are the results from Vibrational Circular Dichroism (VCD), Polarized Optical Microscopy (POM), reactIR ATR-FTIR spectrometer and Atomic Force Microscopy (AFM) on these modified materials.

Temperature and solvent vapor switching properties of branched carbodiimde polymers

255th National Meeting (2018)

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