Discipline: Chemistry and Chemical Sciences
Subcategory: Chemistry (not Biochemistry)
Cameron Earl - California Institute of Technology
Co-Author(s): Zuleikha Kurji, Saint Mary's College of California, Oakland, CA
Historically most liquid crystal elastomer synthesis methods, such as the finkleman method, allow for limited incorporation of functional groups. Recently, methods for more modular synthesis methods have been developed. In 2015, the Yakacki group at the University of Colorado at Denver reported the synthesis of a tailorable and programmable LCE using a two-stage thiol acrylate Michael addition and photopolymerization. Theoretically, any thiol or acrylate monomer may be incorporated into this system, thus allowing for addition of function groups to tailor the LCE’s properties. However, thiols are subideal for this application as they are difficult to synthesize, have a low odor threshold (~0.011ppm), and di- and tetrafunctional thiols are minimally available commercially. Terminal alcohols, in contrast, are effectively odorless, more shelf-stable, and readily commercially available in a large variety. Using an oxa-michael addition can create a system with superior modularity. With heating both triflic and tosyl acid were found to successfully catalyze the polymerization and crosslinking of a model diacrylate with di- and tetra-functional terminal alcohols. Although traditional heating methods were able to activate the reaction, microwave irradiation is ideal as it selectively facilitates the oxa-michael addition over an acrylate-acrylate side reaction. A small molecule reaction monitored using NMR spectroscopy is being used to investigate the reaction further.
Funder Acknowledgement(s): EFRI-ODISSEI: 1332271 ; EFRI-REM
Faculty Advisor: Julie A Kornfield, firstname.lastname@example.org
Role: I conducted all experiments and took all spectra under the guidance of Zuleikha Kurji.