Hostname: page-component-8448b6f56d-dnltx Total loading time: 0 Render date: 2024-04-25T01:38:50.522Z Has data issue: false hasContentIssue false
  • English
  • Français

Side Chain Liquid Crystalline Thermoplastic Elastomers for Actuator and Electromechanical Applications

Published online by Cambridge University Press:  01 February 2011

Eric Verploegen ,
LaRuth C. McAfee ,
Lu Tian ,
Darren Verploegen  and
Paula T. Hammond
Eric Verploegen
Affiliation:
ericv@mit.edu, MIT, NE47-481, 77 Massachusetts Ave., Cambridge, MA, 02139, United States, 617 947 9762
LaRuth C. McAfee
Affiliation:
laruthcm@mit.edu, MIT, Chemical Engineering, United States
Lu Tian
Affiliation:
lutian@mit.edu, MIT, Chemical Engineering, United States
Darren Verploegen
Affiliation:
darrenv@mit.edu, MIT, Chemical Engineering, United States
Paula T. Hammond
Affiliation:
hammond@mit.edu, MIT, Chemical Engineering, United States
Get access

Abstract

The synthesis of a polystyrene-b-polyvinylmethylsiloxane-b-polystyrene diblock and triblock copolymer functionalized with liquid crystals exhibiting a smectic C* phase on the PVMS central block is described. The synthetic route is based on the anionic polymerization of styrene and trimethyltrivinylsiloxane monomers and the functionalization of resulting triblock copolymers. The resulting polymer can self assemble into a thermoplastic elastomer where the high Tg styrene blocks serve as physical crosslinks for a low Tg siloxane block. The presence of a smectic liquid crystalline phase and the block copolymer mesophase are observed across various temperature ranges depending on the length of the spacer connecting the liquid crystalline moiety to the polymer backbone. The influence of mechanical deformation upon the morphologies of the liquid crystalline and block copolymer mesophases was investigated. The interactions between the smectic LC and the block copolymer morphologies and their influence upon their respective orientations in response to shear fields are detailed. The parallel-transverse orientation of the hexagonally close packed (HCP) cylinders of the block copolymer morphology and the smectic liquid crystalline phase, respectively, was observed for melt fiber drawn samples. However, the transverse-perpendicular orientation was observed for liquid crystalline block copolymers that experienced oscillatory shear. The transverse orientation of HCP cylinders was observed while shearing took place above the smectic to isotropic transition temperature, indicating that the presence of an isotropic liquid crystalline phase alters the orientation of the block copolymer morphology. Additionally, it was found that the spacer length was a key factor in the clearing points for the smectic liquid crystalline phase, as well as significantly influencing the nanophase segregation of the block copolymer.

Keywords

morphologyx-ray diffraction (XRD)nanostructure
Type
Research Article
Information
MRS Online Proceedings Library (OPL) , Volume 889: Symposium W – Electroresponsive Polymers and Their Applications , 2005 , 0889-W05-09
Copyright
Copyright © Materials Research Society 2006

Access options

Get access to the full version of this content by using one of the access options below. (Log in options will check for institutional or personal access. Content may require purchase if you do not have access.)

References

REFERENCS

1. Yamada, M.; Itoh, T.; Hirao, A.; Nakahama, S.-I.; Watanabe, J. High Perform. Polym. 1998, 10, 131.Google Scholar
2. Moment, A. J.; Miranda, R.; Hammond, P. T. Macromol. Rapid Commun. 1998, 19, 573.Google Scholar
3. Omenat, A.; Lub, J.; Fischer, H. Chem. Mater. 1998, 10, 518.Google Scholar
4. Merenga, A.; Shilov, S. V.; Kremer, F.; Ober, C. K.; Brehmer, M. Macromolecules 1998, 31, 9008.Google Scholar
5. Sentenac, D.; Demirel, A. L.; Lub, J.; de Jeu, W. H. Macromolecules 1999, 32, 3235.Google Scholar
6. Figueriedo, P.; Geppert, S.; Brandisch, R.; Bar, G.; Thomann, R.; Spontak, R. J.; Gronski, W.; Samlenski, R.; Müller-Buschbaum, P. Macromolecules 2001, 34, 171.Google Scholar
7. Anthamatten, M. L.; Wu, J.-S.; Hammond, P. T. Macromolecules 2001, 34, 8574.Google Scholar
8. Otero, T. F.; Sansiñena, J. M. Bioelectroch. Bioener. 1997, 42, 117.Google Scholar
9. Kucernak, A. R.; Muir, B. Electrochim. Acta 2001, 46, 1313.Google Scholar
10. Donnio, B.; Wermter, H.; Finkelmann, H. Macromolecules 2000, 33, 7724.Google Scholar
11. McAfee, L.C.; Hammond, P.T. Abstr. Pap. Amer. Chem. Soc.-POLY Part 2 2002 224, 570.Google Scholar
12. McAfee, L.C.; Hammond, P.T. Abstr. Pap. Amer. Chem. Soc.-POLY Part 2 2003 225, 674.Google Scholar
13. Svensson, M.; Helgee, B.; Skarp, K.; Andersson, G. J. Mater. Chem., 1998 8(2), 353–362.Google Scholar
14. Guarini, K.; Black, C.T.; Yeung, S.H.I., Advanced Materials 2002, 14, (18), 1290–1294.Google Scholar
15. Stien, P.; Finkelmann, H.; Martinoty, P., The European Physics Journal E 2001, 4, 255–262.Google Scholar
16. Osuji, C.; Ferreira, P. J.; Mao, G.; Ober, C. K.; Vander Sande, J. B.; Thomas, E. L., Macromolecules 2004, 37, (26), 9903–9908.Google Scholar