Related papers: Negative energy elasticity in a rubberlike gel
We performed parallel study of calorimetric and high-frequency shear modulus behavior of Zr-based metallic glasses after deep relaxation just below the glass transition. It is shown that deep relaxation results in the appearance of a strong…
The shear modulus G of two glass-forming colloidal model systems in d=3 and d=2 dimensions is investigated by means of, respectively, molecular dynamics and Monte Carlo simulations. Comparing ensembles where either the shear strain gamma or…
We show that non-entangled polymers display an elastic-like behaviour at a macroscopic scale (probed at some 0.100 mm thickness) up to at least hundred degrees above the glass transition temperature. This observation, found under…
Despite the critical importance of the elastic properties of modern materials, there is not a singular model that can predict the modulus to an accuracy needed for industrial glass design. To address this problem, we propose an approach to…
A wide range of thermoreversible gels are prepared by cooling down to ambient temperature hot aqueous polymer solutions. During the sol-gel transition, such materials may experience a volume contraction which is traditionally overlooked as…
We investigate the impact of nanoparticles (NP) on the fragility and cooperative string-like motion in a model glass-forming polymer melt by molecular dynamics simulation. The NP cause significant changes to both the fragility and the…
We present a theory for the elasticity of cross-linked stiff polymer networks. Stiff polymers, unlike their flexible counterparts, are highly anisotropic elastic objects. Similar to mechanical beams stiff polymers easily deform in bending,…
The Young's modulus $E$ is the key mechanical property that determines the resistance of solids to tension/compression. In the present work, the correlation of the quantity $E$ with such characteristics as the total molar mass $M$ of alloy…
We propose a theory based on non-equilibrium thermodynamics to describe the mechanical behavior of an active polymer gel created by the inclusion of molecular motors in its solvent. When activated, these motors attach to the chains of the…
We report that both shear and bulk moduli, not only shear modulus, are critical parameters involved in both homogeneous and inhomogeneous flows in metallic glass. The flow activation energy (\Delta F) of various glasses when scaled with…
The solvent quality determines the collapsed or the expanded state of a polymer. For example, a polymer dissolved in a poor solvent collapses, whereas in a good solvent it opens up. While this standard understanding is generally valid,…
We study the linear dynamic mechanical response of monodomain nematic liquid crystalline elastomers under shear in the geometry that allows the director rotation. The aspects of time-temperature superposition are discussed at some length…
Entropy is a difficult concept to teach using real-world examples. Unlike temperature, pressure, volume, or work, it's not a quantity which most students encounter in their day-to-day lives. Even the way entropy is often qualitatively…
Transport coefficients and dielectric relaxation in liquids are often treated as distinct manifestations of molecular dynamics. We show that, in polar liquids, orientational dipolar fluctuations generate a substantial contribution to the…
Several surfactant molecules self-assemble in solution to form long, flexible wormlike micelles which get entangled with each other, leading to viscoelastic gel phases. We discuss our recent work on the rheology of such a gel formed in the…
A new result enables direct calculation of thermoelastic damping in vibrating elastic solids. The mechanism for energy loss is thermal diffusion caused by inhomogeneous deformation, flexure in thin plates. The general result is combined…
In order to point out the influence of thermal history (fictive temperature) and OH content on the elastic properties of silica glass, we have performed high resolution in situ Brillouin spectra of SiO2 glass from room temperature to the…
The mechanical response of naturally abundant amorphous solids such as gels, jammed grains, and biological tissues are not described by the conventional paradigm of broken symmetry that defines crystalline elasticity. In contrast, the…
The immense dependence of the glass transition temperature $T_g$ on molecular weight $M$ is one of the most fundamentally and practically important features of polymer glass formation. Here, we report on molecular dynamics simulation of…
Boger fluids are viscoelastic liquids having constant viscosity for a broad range of shear rates. They are commonly used to separate the effects of liquid elasticity from viscosity in any experiment. We present an experimental study on the…