Microreología de polímeros asociativos multiuniones en solución acuosa

Abstract

The experimental techniques of optical microrheology and classical rheology have been applied to study the viscoelastic properties of aqueous solution of an associative copolymer (AP) multisticker in the unentangled semidiluted regimen of concentration. Polymer chains consists of polyacrylamides (99 %mol), hydrophobically modified with low amounts ($ \le $1 % mol) of N,N-dioctylacrylamide (DOAM). Under certain physicochemical conditions these AP self assemble in aggregates of nanometric size to form physical transitory microgeles, resulting in viscoelastic fluids. The passive microrheological technique uses dynamic light scattering to obtain the information of the local dynamic properties of aqueous solutions of associating polymers. With these experimental techniques the range of frequencies is extended up to 50,000~s$^{ - 1}$, allowing to obtain more information of the moduli G'($\omega )$ y G''($\omega )$. In this work, a study of the concentration and diameter of tracer particles also the concentration of AP on the viscoelastic properties has been performed. The viscoelastic behavior of aqueous solutions of AP has been interpreted using the theoretical model of Rubinstein and Semenov [1].