A Current Opinion on Electrophoretic Deposition in Pulsed and Alternating Fields

Abstract

Electrophoretic deposition (EPD) is a colloidal production process developed in the early 20th century. Industrial scale EPD for the production of electronic components and phosphorescent screens and in the form of cataphoretic painting has known some success. Despite its limited practical applications, the inherent versatility of EPD has never ceased to fuel research into this technique. One of the major drives of this research was to render the method more environmentally friendly by enabling deposition from aqueous suspensions. One particular route, suggested to circumvent the problems caused by the use of water in EPD, is the use of alternating or pulsed fields. Recently, the use of alternating fields in EPD has been investigated for the deposition of biological matter in the form of cells and molecules. With this new avenue of research opening up and coinciding with a rise in biotechnological processes, one can expect a renewed interest in traditional EPD and fundamental research on the use of pulsed and alternating fields in this technique. Hence, this review attempts to summarize a century's worth of both fundamental and applied research for scientists venturing into the field of EPD.

Influence of short chain organic acids and bases on the wetting properties and surface energy of submicrometer ceramic powders

“…The calculated values are within a 10°margin, in most cases an underestimation, compared to the experimental data summarized in Table 2. The deviation between calculated and measured value is the strongest for cyclohexane for which evaporation also adversely affects the accuracy of the measured values [11]. Further deviation is caused by the use of an average dispersive energy value.…”

“…Hence it is suggested to use precompacted powder pellets instead of loosely packed powder in a glass tube for assessing the wetting behaviour of submicrometer particles [11]. In order to eliminate the need for a reference liquid, the pore geometry factor f is calculated from the pore radius, r c , sample porosity, e, and sample radius, R as [11]:…”

“…In order to eliminate the need for a reference liquid, the pore geometry factor f is calculated from the pore radius, r c , sample porosity, e, and sample radius, R as [11]:…”

“…The capillary rise measurements were carried out using the procedure and setup described elsewhere [11]. For each experiment the dimensions of a cold isostatically pressed (200 MPa) cylindrical powder pellet were measured by means of a digital calliper (Digimatic, Mitutoyo).…”

“…In this work, a recently developed modified Washburn procedure [11] was used to quantify the influence of different short chain organic molecules on the wetting properties of submicrometer alumina particles. This modified Washburn technique is based on the use of reproducibly precompacted powder samples instead of loosely packed powder in a glass tube.…”