Department of Civil & Environmental Engineering and California NanoSystems Institute, University of California, Los Angeles, Los Angeles, California, USA.
Langmuir. 2010 Feb 16;26(4):2528-37. doi: 10.1021/la9028113.
Extended DLVO interaction potentials were determined for spherical particles approaching nanopatterned substrates using the numerical surface element integration (SEI) technique. In most cases, nanopatterned ("rough") surfaces produced smaller interaction potentials than chemically identical planar ("smooth") surfaces. For unfavorable scenarios, electrostatic double layer and acid-base potentials were reduced to a greater extent than van der Waals potentials, which made rough surfaces "more attractive" than smooth ones. Two influential surface morphological descriptors emerged: (1) the ratio of particle size to asperity size, a/r, and (2) the ratio of asperity separation to asperity size, p/r. As a/r increased, particle-substrate interaction energy decreased, while the opposite was true for p/r. The simple morphological descriptors gave rise to an analytical model based on the Derjaguin integration (DI) method that compared reasonably well with numerical SEI results, where the size and density of nanopatterned surface features dictated the magnitude of interaction potentials. In fact, changes in the size of nanopatterned surface features impacted the magnitudes of interaction potentials to the same extent as similar changes in the magnitudes of acid-base free energy and zeta potential, which begs the question, "is surface morphology a 'scapegoat' or a primary consideration when defining particle-substrate interactions?"
使用数值表面单元积分（SEI）技术确定了球形颗粒接近纳米图案化基底时的扩展 DLVO 相互作用势能。在大多数情况下，纳米图案化（“粗糙”）表面产生的相互作用势能小于化学上相同的平面（“光滑”）表面。对于不利的情况，静电双电层和酸碱势比范德华势降低得更大，这使得粗糙表面比光滑表面“更具吸引力”。出现了两个有影响力的表面形貌描述符：（1）颗粒尺寸与粗糙度尺寸的比，a/r，和（2）粗糙度间距与粗糙度尺寸的比，p/r。随着 a/r 的增加，颗粒-基底相互作用能减小，而对于 p/r 则相反。简单的形貌描述符产生了一个基于 Derjaguin 积分（DI）方法的分析模型，该模型与数值 SEI 结果相当吻合，其中纳米图案化表面特征的尺寸和密度决定了相互作用势能的大小。事实上，纳米图案化表面特征尺寸的变化对相互作用势能的影响程度与酸碱自由能和 zeta 电位的类似变化相同，这就引出了一个问题，“在定义颗粒-基底相互作用时，表面形貌是‘替罪羊’还是主要考虑因素？”
