Effect of the Specific combination of the Applied Voltage and substrate gap of Electrophoretic deposition on the yield and purity of Montmorillonite

The Cloisite Na-Montmorillonite (CNa-MMT) available in the market contains other silicates, such as beidellite, quartz, cristobalite and tridymite. This study explores the potential of electrophoretic deposition (EPD) to improve the purity of CNa-MMT as an important nanoclay filler of nanocomposites, at least for construction materials, food containers, environmental remediation, wound management and sports gear applications. A program of procedures was developed using AUTOLAB p/g for the conduct of EPD. Stainless steel strips were used as electrodes during EPD. XRD of EPD deposits was performed using a Shimadzu XRD-700 with a copper target. Two levels of applied potential were used: high potential “HP”, low potential “LP”, and electrode gap; high electrode gap “HeG” and low electrode gap “LeG”, were investigated for their effects on the yield and purity of CNa-MMT deposits. Analysis of Variance for the two-factor fixed effect model was performed to determine the effects of the factors and their interaction on the yield of CNa-MMT EPD deposits at a 95% confidence level. Results showed significant effects of applied potential, electrode gaps and their interaction on the yield and purity of CNa-MMT. The specific combination of HP-LeG resulted in the highest yield of Na-MMT deposits, while low potential levels (LP) at any electrode gap had a low yield. Interaction plots also showed that low gap (LeG) has a higher slope than high gap (HeG), suggesting that a slight increase in applied potential at a low electrode gap (LeG) will result in a higher increase in the dry Na-MMT EPD deposit than with the same level of potential at a high electrode gap (HeG). Results further showed that even though HP-HeG and LP-LeG experienced the same effect of the electric field, HP-HeG resulted in a higher yield than LP-LeG. Furthermore, XRD showed that the dry Na-MMT EPD deposits swelled and attained higher purity than the commercially available Cloisite Na-MMT.