Project:	Photo-driven isomerization of performance elastomers towards tailorable properties
Disciplines:	Chemistry, Chemical Engineering, Materials Science
Mentor:	Jack Saltiel, Professor, (CCE), jsaltiel@fsu.edu, Phone: 850-644-5405
Mentor URL:	https://www.chem.fsu.edu/~jsaltiel/  (opens in new window)
Background:	NOTE: This project is being offered by a Caltech alum and is open only to Caltech students. The project will be conducted at Florida State University in Tallahassee, Florida. The project concerns altering the cis/trans ratio of double bonds along polymer chains. The mentor is a foremost authority on cis/trans photoisomerization.
Description:	Ring opening metathesis polymerization (ROMP) is a powerful synthetic technique that affords a variety of performance elastomers based on the size and type of cycloolefin monomers used.1-3 Many of the commercially available ROMP catalysts produce polymers with a statistical distribution of cis or trans olefin isomers within the backbone microstructure with little degree of control. The ratio of cis and trans isomers within elastomers is well known to govern many important properties such as resilience, impact resistance, toughness, and modulus.4 Advanced properties, such as strain hardening, are also possible.5 In this project, 1-2 REU students will work on a collaborative effort between the PIs (Saltiel and Kennemur) to investigate photo-driven isomerization 6-8 of polymeric materials produced from ROMP in an effort to modulate the cis/trans content within the backbone. By producing a method to control and predict the cis/trans content. A large variety of elastomeric materials can be realized from a single starting material.
References:	1. Neary, W. J.; Kennemur, J. G. "Polypentenamer Renaissance: Challenges and Opportunities," ACS Macro Lett. 2019, 8, 46. https://doi.org/10.1021/acsmacrolett.8b00885. 2. Martinez, H.; Ren, N.; Matta, M. E.; Hillmyer, M. A. "Ring-opening metathesis polymerization of 8-membered cyclic olefins," Polym. Chem. 2014, 5, 3507. http://dx.doi.org/10.1039/C3PY01787G. 3. Grubbs, R. H. Handbook of Metathesis; Wiley-VCH: Weinheim, Germany, 2003; Vol. 3. 4. Hiemenz, P. C.; Lodge, T. Polymer Chemistry; 2nd ed.; CRC Press: Boca Raton, 2007. 5. López-Barrón, C. R.; Rohde, B.; Zabula, A. V.; Schaefer, J. J.; Throckmorton, J. A. "Molecular Orientation and Strain-Induced Crystallization in trans-Polypentenamer," Macromolecules 2020, 53, 1356. https://doi.org/10.1021/acs.macromol.9b02391. 6. Saltiel, J.; Neuberger, K. R.; Wrighton, M. "The Nature of the Intermediates in the Sensitized Cis-Trans Photoisomerization of Alkenes" J. Am. Chem. Soc. 1969, 91, 3658-3659. 7. Saltiel, J.; Wrighton, M. "Acetone-Sensitized Cis-Trans Photoisomerization of Octa-2,6-dienes" J. Chem. Soc., Chem. Commun. 1972, 129-130. 8. Saltiel, J.; Charlton, J. L. "Cis-Trans Isomerization of Olefins" in Rearrangements in Ground and Excited States, (P. de Mayo, Ed.), 1980, Vol III, 25-89.
Student Requirements:	A laboratory chemistry course would be useful background.
Programs:	This AO can be done under the following programs:   Program    Available To        SURF    Caltech students only  Click on a program name for program info and application requirements.