Related Experiment Video
Updated: Jun 22, 2026

Synthesis of Terpolymers at Mild Temperatures Using Dynamic Sulfur Bonds in Poly(S-Divinylbenzene)
Published on: May 20, 2019
Polymer dimensions in good solvents: crossover from semidilute to concentrated solutions
G Cheng1, W W Graessley, Y B Melnichenko
1Neutron Scattering Sciences Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831, USA.
Abstract:
Using small-angle neutron scattering, we studied the variation of the polymer radius of gyration (R_{g}) as a function of polymer concentration (varphi) for solutions of a flexible-chain poly(methyl methacrylate) in chloroform. We observed for the first time a distinct crossover between swollen coils in the semidilute regime, where R_{g};{2} proportional, variantvarphi;{-0.26+/-0.03}, and unperturbed coils in the concentrated regime, where R_{g} is independent on concentration. The crossover occurs at varphi;{double dagger} approximately 0.15, a value that agrees reasonably well with varphi;{double dagger} approximately 0.21 +/- 0.035, estimated with a scaling relationship between varphi;{double dagger} and the coil overlap concentration varphi;{*}.
Related Concept Videos
Determination of Molar Masses of Polymers II
Molecular Weight of Step-Growth Polymers
As the step-growth polymerization involves step-wise condensation of monomers, the molecular weight also builds up eventually. Consequently, high molecular weight polymers are obtained at the late stages of the polymerization, where 99% of monomers have been consumed.
The extent of the...
Determination of Molar Masses of Polymers I
Expressing Solution Concentration
Concentrations may be quantitatively assessed using a wide variety of measurement units, each convenient for particular applications. Molarity (M) is a useful concentration unit for many applications in chemistry.
Polymers: Molecular Weight Distribution
Solubility
A solution is a homogeneous mixture composed of a solvent, the major component, and a solute, the minor component. The physical state of a solution—solid, liquid, or gas—is typically the same as that of the solvent. Solute concentrations are often described with qualitative terms such as dilute (of relatively low concentration) and concentrated (of relatively high concentration).
In a solution, the solute particles (molecules, atoms, and/or ions)...

