The nature of anisotropic particles with short - range interactions

نویسندگان

  • Ryan P. Murphy
  • Eric M. Furst
  • Yun Liu
  • Paul D. Butler
چکیده

Anisotropic particles are used widely to control the thermodynamic and rheological properties of pharmaceuticals, cosmetics, food products, composite materials, and cements. In particular, rod-like particle suspensions exhibit unique equilibrium and non-equilibrium states at low particle loadings due to large excluded volumes and orientation-dependent attractions. However, the coupled effects of particle shape and interactions are not quantitatively understood with regard to dynamically arrested states, such as colloidal gels and glasses. To better quantify these coupled effects, a tunable model system of adhesive hard rods (AHR) was synthesized to independently control the particle aspect ratio and the temperature-dependent, short-range attractions. AHR suspensions were composed of octadecyl-coated silica rods suspended in tetradecane, which displayed thermoreversible dynamic arrest transitions. The dynamic moduli and particle dynamics were quantified systematically using macroscopic rheological methods and microscopic quasi-elastic light scattering methods, providing a quantitative map of the gel and glass boundaries as a function of aspect ratio (L/D 3 to 7), particle volume fraction (φ 0.1 to 0.5), and absolute critical temperatures (Tgel 25 °C to 30 °C). Small-angle neutron and X-ray scattering methods probed the arrested AHR microstructure to extract an effective interaction strength between rods on a reduced temperature scale, as defined by a dimensionless sticky parameter, τeff.

برای دانلود متن کامل این مقاله و بیش از 32 میلیون مقاله دیگر ابتدا ثبت نام کنید

ثبت نام

اگر عضو سایت هستید لطفا وارد حساب کاربری خود شوید

منابع مشابه

Novel Colloidal Interactions in Anisotropic Fluids

Small water droplets dispersed in a nematic liquid crystal exhibit a novel class of colloidal interactions, arising from the orientational elastic energy of the anisotropic host fluid. These interactions include a short-range repulsion and a long-range dipolar attraction, and they lead to the formation of anisotropic chainlike structures by the colloidal particles. The repulsive interaction can...

متن کامل

Inverted and multiple nematic emulsions

We investigate experimentally the structures that form when small colloidal particles are suspended in a nematic solvent. These structures are anisotropic, and their formation is driven by interactions arising from the orientational elasticity of the nematic solvent. By using inverted and multiple nematic emulsions composed of water droplets dispersed in a thermotropic liquid crystal, we identi...

متن کامل

Notes on the Statistical Mechanics of Systems with Long-Range Interactions

In these Notes we discuss some thermodynamic and dynamical properties of models of systems in which the two-body interaction potential between particles decays algebraically with their relative distance r at large distances. Typically the potential decays as 1/r d+σ in d dimensions and it may either be isotropic or non-isotropic (as in the case of magnetic or electric dipolar interactions). In ...

متن کامل

Clustering transitions in vibrofluidized magnetized granular materials.

We study the effects of long-range interactions on the phases observed in cohesive granular materials. At high vibration amplitudes, a gas of magnetized particles is observed with velocity distributions similar to nonmagnetized particles. Below a transition temperature compact clusters are observed to form and coexist with single particles. The cluster growth rate is consistent with a classical...

متن کامل

Hydrodynamic interactions enhance gelation in dispersions of colloids with short-ranged attraction and long-ranged repulsion.

We show that discrete element simulations of colloidal gelation must account for hydrodynamic interactions between suspended particles through investigation of gelation in a dispersion of colloids interacting pair-wise via short-ranged attraction and long-ranged repulsion (SALR). These dynamic simulations juxtapose self-assembly with and without hydrodynamic interactions between the particles. ...

متن کامل

ذخیره در منابع من


  با ذخیره ی این منبع در منابع من، دسترسی به آن را برای استفاده های بعدی آسان تر کنید

برای دانلود متن کامل این مقاله و بیش از 32 میلیون مقاله دیگر ابتدا ثبت نام کنید

ثبت نام

اگر عضو سایت هستید لطفا وارد حساب کاربری خود شوید

عنوان ژورنال:

دوره   شماره 

صفحات  -

تاریخ انتشار 2017