PROBLEMS ASSOCIATED WITH processing whole sugarcane crop can be minimised by removing impurities during the clarification stage. As a first step, it is important to understand the colloidal chemistry of juice particles on a molecular level to assist development of strategies for effective clarification performance. This paper presents the composition and surface characteristics of colloidal par...

In this paper we present measurements of the electrophoretic mobility of colloidal particles by using heterodyne detection of light scattering. The measurements have been made up to concentrations of 5.4% silica nanoparticles, with a diameter on the order of 80 nm, in a mixture of 70% toluene and 30% ethanol. To make possible the measurements at these concentrations, the liquid mixture is chose...

The NH3-catalyzed formation of colloidal silica particles from tetra-ethyl-orthosilicate (TEOS) in methanol and ethanol is studied by means of light scattering and Raman spectroscopy. We find that the growth is characterized by an incubation period after which no significant nucleation takes place. The particles have uniform, non-fractal structure and show low polydispersity. In the presence of...

Uniform crystalline colloidal cholesterol particles of narrow size distribution were obtained by precipitation. The method consisted of adding a miscible non-solvent (water) into cholesterol solutions of different alcohols and acetone, without any additives. The properties of the resulting particles depended in a sensitive way on the concentration of all reactants, temperature, pH, ionic streng...

in this study, alkaline colloidal silica was prepared by titration of an alkaline solution such as sodium silicate with silicic acid in constant range of ph  .this constant range of ph was achieved by using concentrated soduim silicate solutions as ph adjusting solutions during titration.the sodium silicate solutions  having a variety of concentrations were passed  through ion-exchange resin to...

We developed a straightforward method to form non-close-packed highly ordered fcc direct and inverse opal silica photonic crystals. We utilize an electrostatically self assembled crystalline colloidal array (CCA) template formed by monodisperse, highly charged polystyrene particles. We then polymerize a hydrogel around the CCA (PCCA) and condense silica to form a highly ordered silica impregnat...

The interaction between cleaved talc surfaces and hydrophobic probe particles, silanized silica and thiolized gold, has been investigated employing the atomic force microscopy (AFM) colloidal probe technique. These model systems have hydrophobicities similar to some of the talc-pitch c s a t T ©

The synthesis of polymer brush decorated silica nano-particles is demonstrated by activator regeneration by electron transfer atom transfer radical polymerization (ARGET ATRP) grafting of poly(tert-butyl methacrylate). ATRP initiator decorated silica nano-particles were obtained using a novel trimethylsiloxane derivatised ATRP initiator obtained by click chemistry. Comparison of de-grafted poly...

Previous experiments have shown that spherical colloidal particles relax to equilibrium slowly after they adsorb to a liquid-liquid interface, despite the large interfacial energy gradient driving the adsorption. The slow relaxation has been explained in terms of transient pinning and depinning of the contact line on the surface of the particles. However, the nature of the pinning sites has not...

We developed an efficient synthesis of monodisperse, highly surface charged, high refractive index ZnS spherical particles by using a gel-sol method. Concentrated solutions of zinc-ammonia-NTA (nitrilotriacetic acid) were reacted with thioacetamide in the presence of gelatin which stabilized the growing particles. We dramatically increased the particle surface charge density by condensing silic...