Macromolecular motions and hydrodynamic radius variation in dilute solutions under shear action

• Published in: Polymer international 2015-06, Vol.64 (6), p.766-772
• Main Authors: He, Xian-ru, Xue, Fei, Chen, Qian, Huang, Guang-su, Zhang, Rui
• Format: Article
• Language: English
• Subjects: Chain dynamics; Chains (polymeric); conformation; Dilution; Drug delivery systems; hydrodynamic radius; Molecular conformation; Rheology; Shear; Shear rate; Ubbelohde viscometer; Viscosity
• ISSN: 0959-8103; 1097-0126
• DOI: 10.1002/pi.4850

Using a new design of Ubbelohde viscometer, shear rate could be controlled precisely and conveniently. When polymer dilute solutions flow under different shear action, polymer chain conformation and hydrodynamic radius could be changed and polymer coils move to flow through a porous medium. The polymer molecular chain motion can be divided into three stages which can be reflected by experimental data of intrinsic viscosity under various shear rates. Understanding the dynamics of single polymer chains and rheological mechanism in dilute polymer solutions under shear stress is essential for fields such as the petroleum and food industries, biomedical materials and drug delivery. Here we present an experimental method for measuring the viscosity of polymer solutions and studying the variation of single polymer chain conformation and the mechanism of molecular motions according to the relationship between the intrinsic viscosity, [η], and the shear rate. Of striking interest is that we find that [η] changing with the shear rate presents three stages which may explain the nature of the viscoelastic performance of polymer solutions and the isolated molecular motions. The significance of these results is the finding of the polymer chain deformation to match the pore throat which has enormous potential implications in drug delivery, genetics and biomedicine © 2014 Society of Chemical Industry.