Rheology measurements

Rheological experiments are often used in colloidal science to characterize the viscoelastic properties of suspensions. Colloidal systems are complex fluids, often with non-Newtonian behavior, and they can exhibit a variety of interesting phenomena. Rheology is the study of the viscoelastic properties of fluids, and by shearing a fluid in a controlled fashion, measurements are carried out characterizing the mechanical response of the material. 

Rheology is an important aspect of colloidal science because many industrial products belong to this class of materials, and they all need to be transported along pipes or chutes, filled into containers, or poured and mixed at some point in their production. The behavior of a material under different flow conditions is therefore a parameter of practical importance because it determines how the material can be transferred and incorporated into products. 

Some examples of typical rheological measurements in soft colloidal materials are 

Quantifying viscoelastic properties by measuring bulk viscosity, 

These measurements also apply to other soft systems such as polymers and surfactant phases. 

---

Raman measurements [INFRARED TECHNOLOGY AND RAMAN SPECTROSCOPY - RAMAN SPECTROSCOPY] (Vol 14) -rheological measurements [RHEOLOGICALMEASUREMENTS] (Vol21)... 

PVC emulsions for piNYL POLYMERS - VINYL Cm ORIDE POLYMERS] pol 24) -rheological measurements [RHEOLOGICAL MTEASUREMTENTS] pol 21)... 

Polyolefin melts have a high degree of viscoelastic memory or elasticity. First normal stress differences of polyolefins, a rheological measure of melt elasticity, are shown in Figure 9 (30). At a fixed molecular weight and shear rate, the first normal stress difference increases as MJM increases. The high shear rate obtained in fine capillaries, typically on the order of 10 , coupled with the viscoelastic memory, causes the filament to swell (die swell or... 

Viscous Hquids are classified based on their rheological behavior characterized by the relationship of shear stress with shear rate. Eor Newtonian Hquids, the viscosity represented by the ratio of shear stress to shear rate is independent of shear rate, whereas non-Newtonian Hquid viscosity changes with shear rate. Non-Newtonian Hquids are further divided into three categories time-independent, time-dependent, and viscoelastic. A detailed discussion of these rheologically complex Hquids is given elsewhere (see Rheological measurements). 

---