Measurement of Chain Dimensions in Dilute Polymer Solutions. A Light Scattering and Viscometric Study of Linear Polyisoprene in Cyclohexane

N. S. Davidson; L. J. Fetters; W. G. Funk; N. Hadjichristidis; W. W. Graessley

doi:10.1021/ma00176a048

Measurement of Chain Dimensions in Dilute Polymer Solutions. A Light Scattering and Viscometric Study of Linear Polyisoprene in Cyclohexane

N. S. Davidson^*, L. J. Fetters, W. G. Funk, N. Hadjichristidis, W. W. Graessley

^*Corresponding author for this work

Research output: Contribution to journal › Article › peer-review

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Abstract

Several methods for obtaining the size of macromolecules in dilute solution were applied to a series of linear polyisoprenes in the thermodynamically good solvent cyclohexane. The polymers, prepared by anionic polymerization, cover a wide range in molecular weight (1.5 X 10⁴< M < 3.4 X 10⁶) and have narrow molecular weight distributions (M_w/M_n< 1.1). The viscometric radius R_Vfthe radius of gyration R_g, the hydrodynamic radius R_H,and the thermodynamic radius R_Twere determined by viscometry and by static and dynamic light scattering. The molecular weight dependences of all four size measures are well-described by power laws (R ∞ M^a). The exponents obtained for R_H, R_V and R_Tagree fairly well with the predicted value of 0.588 for good solvents. The exponent obtained for R_Gis smaller, although R_G/R_H in fact changes rather little over the range of available data. The values ofR_G/R_H,R_V/R_H andR_T/R_Hare in reasonable accord with the theory for self-avoiding coils and with results for polystyrene and poly (α-methylstyrene) in good solvents.

Original language	English (US)
Pages (from-to)	2614-2619
Number of pages	6
Journal	Macromolecules
Volume	20
Issue number	10
DOIs	https://doi.org/10.1021/ma00176a048
State	Published - Oct 1 1987
Externally published	Yes

ASJC Scopus subject areas

Organic Chemistry
Polymers and Plastics
Inorganic Chemistry
Materials Chemistry

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title = "Measurement of Chain Dimensions in Dilute Polymer Solutions. A Light Scattering and Viscometric Study of Linear Polyisoprene in Cyclohexane",

abstract = "Several methods for obtaining the size of macromolecules in dilute solution were applied to a series of linear polyisoprenes in the thermodynamically good solvent cyclohexane. The polymers, prepared by anionic polymerization, cover a wide range in molecular weight (1.5 X 104< M < 3.4 X 106) and have narrow molecular weight distributions (Mw/Mn< 1.1). The viscometric radius RVfthe radius of gyration Rg, the hydrodynamic radius RH,and the thermodynamic radius RTwere determined by viscometry and by static and dynamic light scattering. The molecular weight dependences of all four size measures are well-described by power laws (R ∞ Ma). The exponents obtained for RH, RV and RTagree fairly well with the predicted value of 0.588 for good solvents. The exponent obtained for RGis smaller, although RG/RH in fact changes rather little over the range of available data. The values ofRG/RH,RV/RH andRT/RHare in reasonable accord with the theory for self-avoiding coils and with results for polystyrene and poly (α-methylstyrene) in good solvents.",

author = "Davidson, {N. S.} and Fetters, {L. J.} and Funk, {W. G.} and N. Hadjichristidis and Graessley, {W. W.}",

year = "1987",

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doi = "10.1021/ma00176a048",

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T1 - Measurement of Chain Dimensions in Dilute Polymer Solutions. A Light Scattering and Viscometric Study of Linear Polyisoprene in Cyclohexane

AU - Davidson, N. S.

AU - Fetters, L. J.

AU - Funk, W. G.

AU - Hadjichristidis, N.

AU - Graessley, W. W.

PY - 1987/10/1

Y1 - 1987/10/1

N2 - Several methods for obtaining the size of macromolecules in dilute solution were applied to a series of linear polyisoprenes in the thermodynamically good solvent cyclohexane. The polymers, prepared by anionic polymerization, cover a wide range in molecular weight (1.5 X 104< M < 3.4 X 106) and have narrow molecular weight distributions (Mw/Mn< 1.1). The viscometric radius RVfthe radius of gyration Rg, the hydrodynamic radius RH,and the thermodynamic radius RTwere determined by viscometry and by static and dynamic light scattering. The molecular weight dependences of all four size measures are well-described by power laws (R ∞ Ma). The exponents obtained for RH, RV and RTagree fairly well with the predicted value of 0.588 for good solvents. The exponent obtained for RGis smaller, although RG/RH in fact changes rather little over the range of available data. The values ofRG/RH,RV/RH andRT/RHare in reasonable accord with the theory for self-avoiding coils and with results for polystyrene and poly (α-methylstyrene) in good solvents.

AB - Several methods for obtaining the size of macromolecules in dilute solution were applied to a series of linear polyisoprenes in the thermodynamically good solvent cyclohexane. The polymers, prepared by anionic polymerization, cover a wide range in molecular weight (1.5 X 104< M < 3.4 X 106) and have narrow molecular weight distributions (Mw/Mn< 1.1). The viscometric radius RVfthe radius of gyration Rg, the hydrodynamic radius RH,and the thermodynamic radius RTwere determined by viscometry and by static and dynamic light scattering. The molecular weight dependences of all four size measures are well-described by power laws (R ∞ Ma). The exponents obtained for RH, RV and RTagree fairly well with the predicted value of 0.588 for good solvents. The exponent obtained for RGis smaller, although RG/RH in fact changes rather little over the range of available data. The values ofRG/RH,RV/RH andRT/RHare in reasonable accord with the theory for self-avoiding coils and with results for polystyrene and poly (α-methylstyrene) in good solvents.

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JO - Macromolecules

JF - Macromolecules

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Measurement of Chain Dimensions in Dilute Polymer Solutions. A Light Scattering and Viscometric Study of Linear Polyisoprene in Cyclohexane

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