Field-induced alignment

In order to increase the stability of the field induced alignment of DANS it may be necessary to increase the rigidity of the ... 

This chapter deals with the behavior of block copolymer nanostructures subjected to electric fields. We will consider the thin film behavior, elucidate the parameters governing the electric-field-induced alignment, and finally turn to bulk structures and show novel effects of high field strengths on block copolymer... 

Boker A et al (2003) Electric field induced alignment of concentrated block copolymer solutions. Macromolecules 36(21) 8078-8087... 

Boker A et al (2002) Microscopic mechanisms of electric-field-induced alignment of block copolymer microdomains. Phys Rev Lett 89(13) 135502... 

For the remainder of this section, three examples illustrating the behavior predicted in Table 6.4 are discussed. Singer et al. (28) have extensively investigated field-induced alignment for the azo dye Disperse Red I in polymethyl methacrylate (PMMA). Using a dopant molecule number density of 2.74 X 10 /cm, they showed the reasonably linear behavior of Xxxx pohng field when the film was poled above its Tg and quenched in the... 

The main issues that need to be considered in the approach with mo-lecularly doped polymer are concentration of dopant molecules that must be maximized, electric fields required for poling, retention of field-induced alignment, and compatibility of poling with device concepts. 

Auzinsh, M., A.V. Stolyarov, M. Tamanis, and R. Ferber, Magnetic field induced alignment - orientation conversion Non-linear energv shift and predissociation in Tc2 B 1 state, J. Chem. Phys., 105 p. 37 49 (1996). 

Acharya M, Arumugam GK, Heiden PA (2008) Dual electric field induced alignment of electrospun nanofibers. Macromol Mater Eng 293(8) 666-674... 

Martin, C. A., Sandler, J. K. W., Windle, A. H., Schwarz, M. K., Bauhofer, W., Schulte, K., and Shaffer, M. S. P., Electric field-induced aligned multi-waU carbon nanotube networks in epoxy composites, Polymer, 46, 877-886 (2005). 

Thum-Albrecht, T., DeRouchey, J., Russell, T.P., Kolb, R. Pathways toward electric field induced alignment of block copolymers. Macromolecules 35, 8106 (2002)... 

T Thurn-Albrecht, J. DeRouchey, T. P. Russell, and R. Kolb, "Pathways Toward Electric Field Induced Alignment of Block Copolymers," Macromolecules. 35,8106-8110 (2002). 

It is instructive to compare the ratio an/aj 1.5 for ionic processes with a much higher ratio ajj,/a 10 — 10 for the conductivity due to dielectric losses. In the first case, the orientational nematic potential Wn does not influence the translational motion of ions and cj /a L. In the secmid case, the losses eJJ come in from the field induced alignment of the lOTigitudinal molecular axes against the potential barrier and dramatically depend on Wn whereas losses e" caused by molecular rotation about the longitudinal molecular axes are independent of Therefore, ratios e"n/ "j. (and are very large. 

An electric field induced alignment technique has been recently investigated to position CNTs at specific locations in an alumina matrix as a simple method to fabricate functional ceramics for devices and circuits [77]. The resulting composites showed macroscopically anisotropic characteristics for the electrical conductivity and the mechanical properties. 

Figure 2-8. Variable-temperature cell utilized for the spectroscopic characterization of the electric field-induced alignment of liquid crystals, a) Complete assembly of the accessory, (b) Expanded view of the sample cell.

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