pH was used as the main driving parameter for specifically immobilizing silicon nanowires onto Si3N4 microsquares at the surface of a SiO2 substrate. Different pH values of the coating aqueous solution enabled to experimentally distribute nanowires between silicon nitride and silicon dioxide: at pH 3 nanowires were mainly anchored on Si3N4; they were evenly distributed between SiO2 and Si3N4 at...

This research used atomic force microscopy (AFM) to gain a better understanding of the interactions between muscovite mica and a model colloid used commonly throughout the existing colloid transport literature. The interaction forces between a single crystal muscovite mica disc and a 2.0-μm carboxyl-modified polystyrene latex microsphere attached to a tipless silicon nitride (SiN) cantilever we...

A series of miscible-displacement experiments was conducted to examine the retention and transport behavior of oocysts in natural porous media. Three soils and a model sand were used that differed in physical and geochemical properties. Transport behavior was examined under various treatment conditions to help evaluate retention mechanisms. Significant retention of oocysts was observed for al...

Nanoscale zerovalent iron (NZVI), promising for in situ degradation of many environmental contaminants, has been shown to aggregate reducing reactivity and mobility. Aggregation is attributed to the magnetic attractive forces between particles. In this study an alternating gradient force magnetometer (AGFM) is used to measure magnetic properties of NZVI. The magnetization curve is modeled accor...

Filtration theory does not include the potential influence of pore structure on colloid removal by straining. Conversely, previous research on straining has not considered the possible influence of chemical interactions. Experimental and theoretical studies were therefore undertaken to explore the coupling of physical and chemical mechanisms of colloid straining under unfavorable attachment con...

– We investigate the effect of quenched surface charge disorder on electrostatic interactions between two charged surfaces in the presence of dielectric inhomogeneities and added salt. We show that in the linear weak-coupling regime (i.e., by including mean-field and Gaussian-fluctuations contributions), the image-charge effects lead to a non-zero disorderinduced interaction free energy between...

We here report the nanostructures from combinational self-assembly of two designer lipid-like peptides Ac-A6D-OH and Ac-A6K-NH2 using dynamic light scattering (DLS) and atomic force microscopy (AFM). The synergistic phenomenon is observed by measuring the critical aggregation concentrations (CACs) of these two mixed peptides, in different molar ratios by DLS. The nanoropes were observed in AFM ...

The size of gold nanoparticle aggregates was controlled by manipulating the interparticle interaction. To manipulate the interparticle interaction of gold nanoparticles prepared by citrate reduction, we applied the substitutive adsorption of benzyl mercaptan on the particle surface in the absence of the cross-linking effect. Various experimental techniques such as UV-vis absorption spectroscopy...

Molecular dynamics simulations were used to study the jamming transitions occurring in colloidal dispersions interacting through a short-ranged van der Waals attraction and a longer-ranged electrostatic repulsion as represented by the classical Derjaguin– Landau–Verwey–Overbeek (DLVO) theory. The structural and dynamics properties near the jamming transition were investigated at various paramet...

There are different theories concerning the stability of colloidal suspensions. Most of them arise from the well-known DLVO theory which relates colloidal stability to intermolecular forces between particles. Experimental corroboration of these theories has been obtained mainly by using different optical techniques that analyze changes in the optical properties of the solution while particles a...