Unified Analysis of Thermodynamic and Rheological Properties of High Polymer Solutions. II. Ternary Systems ISABEL M. IRURZUN, TOMA ´ S S. GRIGERA, M. SUSANA CORTIZO, RUBE ´ N V. FIGINI,* MARIANNE MARX-FIGINI Instituto de Investigaciones Fisicoqumı ´cas Teo ´ ricas y Aplicadas (INIFTA), CONICET, CIC y Universidad Nacional de La Plata, C.C. 16, suc. 4, La Plata 1900, Argentina Received 29 January 2001; revised 24 January 2002; accepted 1 March 2002 Published online 00 Month 2002 in Wiley InterScience (www.interscience.wiley.com). DOI: 10.1002/polb.10165 ABSTRACT: We extend to ternary solutions our previous study of conformational, ther- modynamic, and rheological properties of semidilute polymer solutions in good solvent. Osmotic pressure and viscosity measurements were performed in several mixtures of two compatible polymers in a common solvent. Renormalization group results were used to analyze the data, using de Gennes’s blobs model to connect dynamic and conformational properties. © 2002 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 40: 1071–1079, 2002 Keywords: heterogeneous polymers; viscosity; thermodynamics INTRODUCTION The universal behavior of polymer solutions has been experimentally recognized for a long time. Major manifestations of universality are the power-law relationships (the limiting forms of the most general scaling functions) that hold for a wide range of chemically different systems. 1–3 Universality shows up in that the macroscopic properties of dilute and semidilute polymer solu- tions are invariant under a redefinition of the monomer unit. Renormalization group (RG) the- ory exploits this invariance of scale to obtain mac- roscopic relations from the microscopic model of the system, deriving universal laws. To date, RG theory has been successfully ap- plied to the description of binary polymer solu- tions. 4 –18 A reasonable understanding of dilute solutions exists, and progress has also been made in the description of thermodynamic and confor- mational properties of semidilute solutions. The description of dynamic properties is more difficult because of the hydrodynamic interaction, and al- though there are theoretical approaches to its description, a unified treatment of excluded vol- ume and hydrodynamic screening is still unavail- able. In a previous article, 19 we carried out an exten- sive study of binary systems (i.e., solvent plus one polymeric species). We measured both the thermo- dynamic and dynamic properties (osmotic pressure and viscosity) of dilute and semidilute solutions and applied a scheme based on RG theory. Our scheme uses the RG results for osmotic pressure and radius of gyration and extends them to consider also the dynamic properties. Theoretical results agreed with the experimental data. The comparison was made by adjusting a nonuniversal quantity () that de- pends on the chemical nature of the systems and temperature. Once  is experimentally calculated, the behavior of the polymer solution in the whole range from dilute to semidilute limits can be deter- mined. Our previous results indicated that  has different values for static (thermodynamic and con- formational) and dynamic properties. Nevertheless, the scheme supports an extensive analysis, and it is Correspondence to: T. S. Grigera (E-mail: tomas.grigera@ roma1.infn.it) *Deceased Journal of Polymer Science: Part B: Polymer Physics, Vol. 40, 1071–1079 (2002) © 2002 Wiley Periodicals, Inc. 1071