Hydrodynamic properties of regular star-branched polymer in dilute solution

Synthesis and Solution Properties of a Rigid Helical Star Polymer: Three-Arm Star Poly(quinoxaline-2,3-diyl)

“…As also displayed in Figure 5, the obtained g η values are between 4/9 and 0.90 for rigid 24 and flexible stars, 25 respectively; note that the former value is calculated for rigid stars with the fixed connection angle. Except for the lowest M w sample, the obtained g η values increase with increasing M w .…”

Intrinsic Viscosity of Wormlike Regular Three-Arm Stars

“…Further, the g values 0.75 and 0.63 obtained for regular fourand six-arm star polystyrenes, respectively, in cyclohexane at 34.5 C (Â) 24,25 are ca. 10% smaller than the respective theoretical values 0.82 and 0.70 obtained by Irurzun 19 for the Gaussian regular four-and six-arm star chains in the KR approximation. The KR approximation therefore seems to overestimate g because of the preaveraging of the Oseen tensor.…”

Intrinsic viscosity of wormlike regular four-arm stars

“…[g] of wormlike regular four-arm stars connect the theoretical values at constant d b , and the solid straight lines indicate the respective initial tangents. It is seen that as L À1/2 decreases to 0 (L-N), g Z approaches the above-mentioned value16 0.82, irrespective of the value of d b . Based on these numerical results, it may be concluded that lim LZ ðL; d b Þ ¼ 0:81 7 ðrandom-coil limitÞ:…”

“…We have calculated the KR contribution [Z] KR to the intrinsic viscosity [Z] from Equation 3 The solid curves represent the values calculated from an interpolation formula, which are obtained and discussed in a later subsection. The horizontal line segment indicates the value 0.82 obtained by Irurzun 16 for the Gaussian regular four-arm star chain without excluded volume in the KR approximation. As in the case of the KP regular three-arm star touched-bead model, 10 g Z first decreases and then increases after passing through a minimum, with decreasing L in the range of d b investigated in this study, and the behavior of g Z shows remarkable dependence on d b .…”

“….82 for the four-arm star and 0.90 for the three-arm star, respectively, in the random-coil limit obtained by Irurzun. 16 The lower solid and dashed horizontal line segments indicate the above-mentioned asymptotic values 1/4 for the four-arm star and 4/9 for the three-arm star, respectively, in the thin rod limit. It is seen that g Z,4 is appreciably smaller than g Z,3 for given L and d b , as a natural consequence of the fact that the average chain dimension of polymer chains becomes smaller with an increasing degree of branching.…”