Poly longitudinal structure

Using atomic force microscopy (AFM), Xu et al. [85] showed that similar macromolecular co-assemblies derived from the cylindrical PE brush based on quat-ernized poly[2-(dimethylamino) ethyl methacrylate] (PDMAEMAQ) complexed with short poly(sodium styrene sulfonate) (PSSNa) have distinct longitudinal undulations (Fig. 8), thereby apparently providing experimental proof of a peculiar pearl-necklace structure of IPECs based on such branched PEs. 

Pad ei al. [142] blended a semiflexible, longitudinal PLC copolymer of poly (biphenyl-4,4 -ylene sebacate) (PBS) with chemical structure... 

Early treatment of materials with iodine revealed structures in nylon 6 filaments [191,192]. The longitudinal periodicity of nylon was shown by the differential absorption of the iodine in the crystalline and noncrystalline regions. Hess and Mahl [98] treated poly(vinyl alcohol) fibers with 5% iodine which revealed a long period (16 nm) which relates to the absorption of iodine in the noncrystalline or amorphous regions. Hess et al [193] detected structures of the order of tens of nanometers in cellulose treated with iodine. The fibers were soaked in 12% iodine following homogenization to break them up into fibrils. 

The question arises why cis-polyisoprene, different from poly(vinyl-acetate), shows in its dielectric spectrum the chain reorientation. The reason becomes clear when we look at the chemical constitution of polyisoprene, and focus in particular on the associated dipole moments. Figure 5.22 displays the chemical structure. The main point is that isoprene monomers are polar units which possess a longitudinal component p of the dipole moment, which always points in the same direction along the chain. As a consequence, the longitudinal components of the dipoles of all monomers become added up along the contour, giving a sum which is proportional to the end-to-end distance vector R. In the dielectric spectrum the kinetics of this total dipole of the chain is observable, hence also the chain reorientation as described by the time dependence R t). 

The other stationary periodic pattern has been observed in polymer lyotropic liquid crystals [78]. The smallness of the ratio K-iilK 1 of a poly-g-benzylglutamate solution results in a structure in which the period of the longitudinal domains is of the same order of magnitude as the cell thickness. Due to the high viscosity of the material (7i = 34 P) the time for domain formation exceeds 2 h. If the director was initial-... 

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