Eighteen years ago, Fredrickson et al. [Macromolecules 1992, 25, 2882-2889] predicted that a molten polymer brush possesses a shear modulus that would cause its surface structure to deviate from a liquid. Their prediction, though broadly used, has been largely unchecked. Here, we present experimental data on polystyrene brushes that validate Fredrickson et al.’s prediction. We also present data...

Cherkaev-Gibiansky and Hashin-Shtrikman variational principles are utilized in order to obtain rigorous bounds on the shear modulus of two-phase viscoelastic composites in three dimensions. The simplest class of bounding regions is composed of circles in the complex plane containing four points related to the viscoelastic moduli of the constituents. By taking the intersection of all such circle...

Hydrodynamic and colloidal interactions are explored in concentrated, charge-stabilized colloidal dispersions by measuring the dependence of rheology (e.g., low and high-shear viscosity, high-frequency viscosity, and modulus) and self-diffusivity on salt content, particle size, and concentration. Model, sulfonated polystyrene lactices of varying diameter are prepared and investigated by shear r...

The elastic properties of the human red blood cell membrane have been measured as functions of temperature. The area compressibility modulus and the elastic shear modulus, which together characterize the surface elastic behavior of the membrane, have been measured over the temperature range of 2-50 degrees C with micropipette aspiration of flaccid and osmotically swollen red cells. In addition,...

experimental study of the cyclic behavior of unsaturated materials is more complex than that of the saturated materials due to the required equipment, experience and time. furthering investigations in the field of unsaturated materials is necessary to better understand its complexity and sensitivity of unsaturated cyclic parameters to different determinants such as suction path, stress path, lo...