Effects of Particle Deformability on Interaction between Surfaces in Solutions

Abstract

Interactions between a deformable polymer particle and a solid surface of a mica plate in solutions were investigated using atomic force microscopy (AFM), where the particles have the same surface property but different bulk elasticity. Measurements were done in a solution of cetyltrimethylammonium bromide (CTAB), above its critical micelle concentration (cmc). Under these conditions positively charged layers were formed on both mica and particle surfaces, which induce a high repulsive potential between the approaching surfaces. However, above a critical pressure, the surfaces come in adhesive contact by destroying the adsorbed layers. It was found that the total repulsive force between the surfaces and the force required to adhere the particle to the surface increased significantly if the glass transition temperature of the particle was below the ambient temperature. This indicates that the elastic deformation of the particle as the surfaces are brought together greatly increases the total repulsion within the system. A quantitative interpretation of the data was carried out, using a simple model, which was derived from the theory for elastic body deformation developed by Hughes and White. 1 Results of this study provide significant information on the stability of suspensions of low elastic modulus particles.

Direct AFM measurements of adhesion forces between calcium oxalate monohydrate and kidney epithelial cells in the presence of Ca2+ and Mg2+ ions

“…According to Vakarelski et al [18,19], the slope for the region of constant compliance was measured for the interaction of the crystal with a hard sample (mica), and this value was used later for the calculation of the force/distance curves for the crystal/cell interaction. The difference of the slopes of the constant compliance for soft (cells) and hard (mica) objects could be used for calculation of the elasticity of a soft material, as it is described in Refs.…”

Atomic force microscopy measurement of the elastic properties of the kidney epithelial cells

“…The final form of the data represented as force, F , versus indentation depth, δ, has been corrected for the distance taking into account that the "contact line" (region of constant compliance) is related to the soft body rather than a solid nondeformable body, as explained in the literature [13,[17][18][19].…”

Foam-Film-Stabilized Liquid Bridge Networks in Evaporative Lithography and Wet Granular Matter

“…Surfactants used to stabilize the liquid bridge network were cetyltrimethylammonium bromide (CTAB) (Sigma Aldrich) or Zonyl FSN (DuPont). CTAB is a standard cationic surfactant used in foam, emulsion, and suspension stabilization − with a critical micelle concentration (cmc) of about 1 mM. Zonyl FSN is a water-soluble ethoxylated nonionic fluorosurfactant that modifies surface energies at very low concentrations.…”