Second and third virial coefficients of low-molecular-weight polyisoprene in 1,4-dioxane

Dilute Solution Properties of a Polymacromonomer Consisting of a Polystyrene Main Chain with Polyisoprene Side Chains. Relation of Molecular Parameters to Polymer Segment Interactions

“…Therefore, the positive A 2 of PS–PI PM at the theta temperature for linear PI could be attributed to the interaction between the side-chain and main-chain segments. This is supported by recent our study on relatively short linear PI with a butyl group at one of the chain ends that A 2 in 1,4-dioxane becomes negative at 35.3 °C, when molecular weight is reduced to less than 10 4 . This shows that the interaction between the butyl end and the PI unit is negligibly small; the negative A 2 is attributed to the three-segment interaction among PI segments .…”

“…In Figure 2, A 2 for sample F4 in 1,4-dioxane is plotted against temperature T. It is seen that A 2 is positive at the theta temperature Θ for linear PI, 35.3°C, 23 and vanishes at 31.0°C. The change of Θ from that for linear PI is different from the case for benzyl-PS PM in cyclohexane, whose Θ agreed with that for linear PS in the same solvent, but close to the case for PI−PS PM, whose Θ was 5.5°C lower than that for linear PS.…”

“…This shows that the interaction between the butyl end and the PI unit is negligibly small; the negative A 2 is attributed to the three-segment interaction among PI segments. 23 Thus, the positive A 2 of PS−PI PM at 35.3°C is concluded to come from the interaction between the PIunit and the main-chain unit. As mentioned in the Introduction, in the case that the interaction between the side-chain end and the middle of side chain is effective, e.g., PMA−PS PM or butyl-PS PM in cyclohexane, A 2 does not vanish in a wide temperature range.…”

“…The difference (7 nm) between the calculated value and the experimental one is attributable to the contribution of the interaction between PS main chain and PI segments, since the contribution of the interaction between PI and chain-end segments is negligible in this solvent. 23 This contribution may be considered by adding the following term to λ −1 :…”

Efimov-like phase of a three-stranded DNA and the renormalization-group limit cycle

“…The difficulty of course lies in separating the melting of the Efimov DNA from that of a Watson-Crick and Hoogsteen paired triple-stranded DNA. (ii) A different thermodynamic study would be the virial coefficients via the osmotic pressure of dilute solutions [55]. The third virial coefficient will give H(Λ), Eq.…”