Inorganic Materials Research Program, School of Physical and Chemical Sciences, Queensland University of Technology, 2 George Street, GPO Box 2434, Brisbane Qld 4001, Australia.
J Colloid Interface Sci. 2010 Apr 15;344(2):563-74. doi: 10.1016/j.jcis.2009.12.065. Epub 2010 Jan 11.
In paper has been to investigate the morphological patterns and kinetics of PDMS spreading on silicon wafer using combination of techniques like ellipsometry, atomic force microscope (AFM), scanning electron microscope (SEM) and optical microscopy. A macroscopic silicone oil drops as well as PDMS water based emulsions were studied after deposition on a flat surface of silicon wafer in air, water and vacuum. Our own measurements using an imaging ellipsometer, which also clearly shows the presence of a precursor film. The diffusion constant of this film, measured with a 60,000 cS PDMS sample spreading on a hydrophilic silicon wafer is D(f)=1.4x10(-11) m(2)/s. Regardless of their size, density and method of deposition, droplets on both types of wafer (hydrophilic and hydrophobic) flatten out over a period of many hours, up to 3 days. During this process neighbouring droplets may coalesce, but there is strong evidence that some of the PDMS from the droplets migrates into a thin, continuous film that covers the surface in between droplets. The thin film appears to be ubiquitous if there has been any deposition of PDMS. However, this statement needs further verification. One question is whether the film forms immediately after forced drying, or whether in some or all cases it only forms by spreading from isolated droplets as they slowly flatten out.
本文采用椭偏仪、原子力显微镜（AFM）、扫描电子显微镜（SEM）和光学显微镜等技术，研究了聚二甲基硅氧烷（PDMS）在硅片上的形态模式和动力学。研究了宏观硅油滴以及 PDMS 水性乳液在空气、水和真空中沉积到硅片平坦表面后的情况。我们使用成像椭偏仪进行了自己的测量，该测量也清楚地显示了存在前体膜。用 60,000 cS PDMS 样品在亲水硅片上展开时，该薄膜的扩散常数 D(f)=1.4x10(-11) m(2)/s。无论其大小、密度和沉积方法如何，两种类型的晶圆（亲水和疏水）上的液滴在数小时内，最长可达 3 天的时间内都会变平。在此过程中，相邻的液滴可能会合并，但有强有力的证据表明，液滴中的一些 PDMS 会迁移到覆盖液滴之间表面的薄而连续的薄膜中。如果有任何 PDMS 的沉积，那么这种薄膜似乎无处不在。然而，这一说法需要进一步验证。一个问题是，薄膜是否在强制干燥后立即形成，或者在某些或所有情况下，它是否仅通过从缓慢变平的孤立液滴中扩散形成。
