Photoinduced Shuttling Dynamics of Rotaxanes in Viscous Polymer Solutions

Jagesar, Dhiredj C. and Fazio, Sandro M. and Taybi, Jimmy and Eiser, Erika and Gatti, Francesco G. and Leigh, David A. and Brouwer, Albert M. (2009) Photoinduced Shuttling Dynamics of Rotaxanes in Viscous Polymer Solutions. Advanced Functional Materials, 19 (21). p. 3440. ISSN 1616301X DOI 10.1002/adfm.200900668

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Abstract

The effect of external friction, caused by medium viscosity, on the photoinduced translational motion in a rotaxane-based molecular shuttle 1 is investigated. The shuttle is successfully operated in solutions of poly(methacrylonitrile) (PMAN) of different molecular weights in MeCN and PrCN. The viscosity of the medium is tuned by changing the PMAN concentration. The rheological behavior of the polymer solution gives insight into the structure of the polymer solution on the microscopic scale. In PrCN, the entanglement regime is reached at lower concentration than in MeCN. This is also reflected by the effect on the shuttling: in the PrCN/PMAN system, a larger viscosity effect is observed compared to MeCN/PMAN. The shuttle is found to be slowed down in the polymer solutions but is still active at high viscosities. The observed retardation effect on the kinetics of shuttling in MeCN/PMAN and PrCN/PMAN can be correlated to the PMAN concentration through the hydrodynamic scaling model. The Stokes-Einstein relationship proves inadequate to correlate the shuttling rates to macroscopic viscosity, but the dependence of the shuttling rate on the bulk viscosity fits well to a commonly observed power-law relationship. The viscosity effect on the shuttling is found to be weak in all cases.

Item Type: Article
Uncontrolled Keywords: 09AREP; BPI
Subjects: 99 - Other
Divisions: 99 - Other
Journal or Publication Title: Advanced Functional Materials
Volume: 19
Page Range: p. 3440
Identification Number: 10.1002/adfm.200900668
Depositing User: Sarah Humbert
Date Deposited: 23 Jul 2010 11:29
Last Modified: 23 Jul 2013 09:57
URI: http://eprints.esc.cam.ac.uk/id/eprint/1516

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