Poly permanent dipole moment

An example of polymer solutions is P(VDF/TrFE)/DMF solution [49] (Fig. 11). Poly(vinylidene-co-trifluoroethylene) (P(VDF/TrFE)) is known as a strong dielectric polymer. It possesses a permanent dipole moment in the main chain. The electric field frequency dependence of the relative viscosity was measured by a capillary rheometer. The result showed a positive ER effect at 10 Hz whereas it showed a negative ER effect at 1 kHz. 

The dipolar interactions between polar host CDs and included guests with permanent dipole moments are considered to affect at least the conformations and structures of soluble small-molecule guest/host CD-ICs.Our observations of the preference for inclusion of poly (e-caprolactone) (PCL) over poly(L-lactic acid) (PLLA) chains in both dissolved and crystalline suspended a-CD (a-CDcs), as well as the displacement of PLLA chains by PCL from PLLA-a-CD-ICs when suspended in PCL solution, indicate that dipole-dipole electrostatic interactions may not be critical to the formation of polymer-CD-ICs. If they were, then we might expect PLLA to be preferentially included in a-CD compared to PCL, because two PLLA repeat units and two ester group dipoles occupy each a-CD, while only single PCL... 

Examples of polymers that have a piezoactive response are poled poly(vinylidene fluoride) (PVDF) (151) and its copolymers with trifluo-roethylene co(VDF-TrFE) (152), and the family of odd nylons (153) (see Piezoelectric Polymers). These are partially crystalline materials in which the crystalline regions have a permanent electric dipole moment. These polymers show ferroelectric switching behavior indicating that after poling they have a net... 

For long-chain molecules there are different geometric possibilities for the orientation of molecular dipole vectors with respect to the backbone. Following the notation of Stockmayer (1967), polymers are classified as type A (with dipoles fixed parallel to the mainchain, e.g., ds-l,4-polyisoprene and polyethers), type B [with dipole moments rigidly attached perpendicular to the mainchain e.g., poly (vinyl acetate) and most synthetic polymers], or type C [with a more-or-less flexible polar sidechain e.g.,poly(n-alkyl methacrylate)s]. However, a polymer possessing only one type of dipole moment is an exceptional case. The timescale (speed) of each polarization (and subsequent relaxation) process will determine whether this process will be monitored by a particular dielectric technique. Characteristics and fundamental peculiarities of relaxations generally found in polymers are discussed hereafter. Note that cases where finite polarization is present even in the absence of an external field (e.g., the permanent polarization in ferroelectrics) are not considered. 

The main solute-column interactions can be classified as dispersion forces and dipole-dipole interactions. The dispersion forces are present in any solute-solvent system, a hydrocarbon solute interacting with a nonpolar paraffin being often shown as an example. The polar solute molecules have permanent dipoles that can interact with those of the polar phases on occasions, the dipole moments can also be induced in certain solute molecules in the presence of highly polar column materials. Dipole-dipole interactions are clearly evident in the separations of alcohols, esters, amines, aldehydes, and so on, on the poly glycol, polyamide, polyester, or cyanoalkylsilicone stationary phases. 

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