Das Pradipta Kr
Global R&D Tata Steel, Jamshedpur, India.
Electrophoresis. 2016 Jan;37(2):347-55. doi: 10.1002/elps.201500374. Epub 2015 Nov 27.
Surface properties of nanoparticle are of high importance in the field of biotechnology, drug delivery and micro/nanofabrication. In this article, we developed a comprehensive theoretical model and subsequently solved that numerically to study the effect of thermodiffusion of ions on surface charge properties of nanoparticle. The theoretical study has been done considering silica nanoparticle for two aqueous solutions NaCl and KCl. The effect of solution pH in conjunction with nanoparticle temperature on surface charge density has been obtained for different salt concentrations (1, 10 and 100 mM) and nanoparticle size (diameter of 2 and 100 nm). It is observed from the results that with increasing temperature of the nanoparticle, the negative surface charge density gets higher due to increasing thermodiffusion effect. It is also found out that the magnitude of surface charge density is higher for KCl solution than NaCl solution under same condition which is attributed mostly due to less thermodiffusion of counterions for KCl than NaCl. Present study also shows that magnitude of surface charge density decreases with increasing nanoparticle size until it reaches a limiting value (called critical size) above which the effect of nanoparticle size on surface charge density is insignificant.
纳米颗粒的表面性质在生物技术、药物递送以及微纳制造领域具有高度重要性。在本文中，我们开发了一个全面的理论模型，并随后对其进行数值求解，以研究离子热扩散对纳米颗粒表面电荷性质的影响。该理论研究是针对二氧化硅纳米颗粒在两种水溶液（NaCl和KCl）中进行的。对于不同的盐浓度（1、10和100 mM）以及纳米颗粒尺寸（直径为2和100 nm），已得出溶液pH值与纳米颗粒温度共同作用对表面电荷密度的影响。从结果中观察到，随着纳米颗粒温度的升高，由于热扩散效应增强，负表面电荷密度会变得更高。还发现，在相同条件下，KCl溶液的表面电荷密度大小高于NaCl溶液，这主要归因于KCl的反离子热扩散比NaCl少。本研究还表明，表面电荷密度大小随着纳米颗粒尺寸的增加而减小，直到达到一个极限值（称为临界尺寸），超过该尺寸后，纳米颗粒尺寸对表面电荷密度的影响就不显著了。
