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

Inoue, Kouta; Yamamoto, Seiji; Nakamura, Yo

doi:10.1021/ma401727c

Cited by 12 publications

(21 citation statements)

References 32 publications

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“…Although the above theoretical arguments, mainly based on the Flory approximation, can provide an intuitive scaling relation between chain size and chain parameters (grafting density, side-chain length, and backbone length), quantitative analysis is still the weakness when concerning the intrinsic scale, i.e., persistence length. Alternatively, the quasi-two-parameter (QTP) theory, developed by Yamakawa et al, has been proved both theoretically and experimentally to be effective for the estimation of l p for chains under good solvent conditions by considering the expansion factor (α s ). − The basic principle is as follows.…”

Section: Theoretical Backgroundmentioning

confidence: 99%

Experimental Validation on Average Conformation of a Comblike Polystyrene Library in Dilute Solutions: Universal Scaling Laws and Abnormal SEC Elution Behavior

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Ding

2021

Macromolecules

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In this work, a sample library of well-defined comblike polystyrenes (PS) has been prepared for the study of average conformation in dilute solutions. The dependences of radius of gyration (R g), intrinsic viscosity ([η]), viscometric radius (R η), and persistence length (l p) on the molar mass (M), grafting density (σ), and degree of polymerization of graft side chains (N g) have been established. First, we have revealed the universal abnormal elution behavior of comblike chains in different size exclusion chromatography (SEC) column systems. A combined theoretical analysis and elution experiment indicates the possible thermodynamic origin, i.e., for chains with the highest stiffness, the anisotropic characteristics and chain end orientation can potentially increase the partition coefficient and retention volume, while the flow-induced forced penetration plays a negligible role. Moreover, the established scalings R η ∼ N g 0.40±0.03σ1/3, R g ∼ (N gσ)0.37±0.01, and l p ∼ σ 0.85±0.09 further indicate that (1) the equivalent viscometric volume is proportional to the mass of individual comblike chains when σ is increased, corresponding to the quasi-3D mass-size growth pattern; (2) the proper consideration of the swelling conformation of side chains is important to capture the essentials of conformational behavior for comblike polymer systems with flexible backbones; and (3) the experimentally established l p–σ dependence by considering the excluded-volume effect is much weaker than the theoretical predictions (l p ∼ σ17/8 and l p ∼ σ7/3). This work provides a comprehensive perspective for understanding the conformational evolution of comblike chains.

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Section: Theoretical Backgroundmentioning

confidence: 99%

Experimental Validation on Average Conformation of a Comblike Polystyrene Library in Dilute Solutions: Universal Scaling Laws and Abnormal SEC Elution Behavior

Pan

Ding

2021

Macromolecules

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“…In bulk, polymacromonomers are rarely entangled (as noted from the viscoelastic behavior) because of the branches having a large volume fraction and diluting the entanglement between the backbones . Nowadays, physical properties of such bottlebrush-like polymacromonomers are attracting extensive research interest. ,− …”

Section: Introductionmentioning

confidence: 99%

Rheo-Optical and Dielectric Study on Dynamics of Bottlebrush-like Polymacromonomer Consisting of a Polyisoprene Main Chain and Polystyrene Side Chains

et al. 2020

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For bottlebrush-type polystyrene polymacromonomer consisting of a polyisoprene main chain and polystyrene side chains (PI-PS-bPM), dynamic birefringence and viscoelasticity measurements were conducted over a wide range of frequencies covering from the glass-to-rubber transition zone to the flow zone. In addition, dynamic dielectric measurements were conducted at low frequencies to selectively detect the end-to-end motion of the main chain (PI) having type-A dipoles. The complex modulus and complex strain-optical coefficient were decomposed into contributions from the main chain and branch on the basis of the modified stress-optical rule, MSOR. The terminal relaxation of the complex modulus and dielectric loss commonly reflected the end-to-end motion of the main chain PI, and their relaxation times, τ G and τ ε , obeyed an empirical relationship established for monodisperse linear type-A chains, τ ε ≅ 2τ G . The dielectric relaxation intensity of the PI main chain, Δε M , was found to be approximately 5 times larger than that expected for linear PI equivalent to this main chain (Δε M = 4.2ϕ main Δε PI with ϕ main being the main chain volume fraction), which suggests that the mean-square end-to-end distance of the main chain is about 5 times larger than that of linear PI, and thus, the main chain is more rigid than linear PI. This result was consistent with an increase in dynamic rigidity of the main chain (compared to PI) deduced from the rheo-optical analysis. Furthermore, the main chain rigidity of PI-PS-bPM was found to be about a half of a previously examined polymacromonomer, PS-PS-bPM, having PS in both branch and backbone. This difference between PI-PS-bPM and PS-PS-bPM was attributed to the branch density per unit length of the main chain that was lower for PI-PS-bPM.

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“…Whereas the side chain molecular weight dependence of λ b −1 in eq 1 for the flexible brushes has been studied experimentally 15,18,19 and theoretically, 16,20−22 a consensus has not always been obtained to date.…”

Section: ■ Introductionmentioning

confidence: 99%

Graft Density Dependence of Main Chain Stiffness in Molecular Rod Brushes

et al. 2015

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The graft density dependence of main chain stiffness in rod brushes composed of a flexible linear polystyrene (PS) main chain and poly(n-hexyl isocyanate) (PHIC) rod side chains has thoroughly been investigated by static light (LS) and small-angle Xray scattering (SAXS) measurements in tetrahydrofuran (THF) at 25°C. A series of statistical graft copolymers having different graft densities (σ) and graft chain lengths (PS-g-HIC-N s -l g , where N s is the weight-averaged degree of polymerization of HIC and l g is the average distance (spacing) of the main chain between the side chain joints) were prepared by the nearly azeotrope radical copolymerizations of styrene (M 1 ) with PHIC macromonomers (M 2 ) (r 1 = 0.84 ± 0.1 and r 2 = 1.1 ± 0.3) in n-hexane or the bulk at 60°C. The compositional heterogeneities of the graft copolymers were carefully characterized by the ratio of the UV to RI signal in the SEC traces and the comparison with those predicted from the theory by Stejskal and Kratochvil [Macromolecules 1987, 20, 2624], implying that they were sufficiently small enough to allow one to study their dimensional characterizations. The graft density dependence of the root-mean-square cross-section radius of gyration (⟨S c 2 ⟩ 1/2 ) and the z-averaged root-mean-square radius of gyration (⟨S 2 ⟩ z 1/2 ) of PS-g-HIC-N s -l g was studied and rationalized as the function of σ and N s . The σ-dependence of ⟨S c 2 ⟩ 1/2 could be quantitatively described by the theory for the semiflexible comb whose main and side chains have different chain stiffness. The weight-averaged degree of polymerization of the main chain (N M ) dependence of ⟨S 2 ⟩ z 1/2 was also quantitatively described by the cylindrical wormlike chain model. It was found that the change in the main chain stiffness (λ b −1

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

Cited by 12 publications

References 32 publications

Experimental Validation on Average Conformation of a Comblike Polystyrene Library in Dilute Solutions: Universal Scaling Laws and Abnormal SEC Elution Behavior

Experimental Validation on Average Conformation of a Comblike Polystyrene Library in Dilute Solutions: Universal Scaling Laws and Abnormal SEC Elution Behavior

Rheo-Optical and Dielectric Study on Dynamics of Bottlebrush-like Polymacromonomer Consisting of a Polyisoprene Main Chain and Polystyrene Side Chains

Graft Density Dependence of Main Chain Stiffness in Molecular Rod Brushes

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