Effects of Photothermal Conversion on the Laser-Photophoresis of Micro-Particles in Liquid Media.

激光光电泳是一种很有前途的迁移和分离液体介质中微粒的技术。然而，光热转换对光吸收微粒的光致行为的影响尚不清楚。在本研究项目中，我们做了以下研究来阐明光热效应对微粒激光致光迁移的影响。1. 光吸收微乳液滴在水中具有周期性膨胀收缩运动的激光光致迁移。：阐明了运动的起源是光热转换，周期性膨胀-收缩运动的机理由三个步骤组成。2. 激光辐照水滴在水中的温度分布。：被辐照液滴正面温度高于液滴背面温度。这种温度分布导致反向光致电泳。3. 激光光电泳法分离血细胞。我们提出了分光法分离红细胞和白细胞的方法。4. 有机溶剂中气泡的形成和捕获。我们发现了激光在有机溶剂中诱导气泡形成和气泡被激光捕获的新现象。5. 有机溶剂中水滴和水溶液水滴的光致发光行为。研究发现，水对1064nm激光的吸收使水滴在有机溶剂中具有复杂的光致发光行为。这些行为不能用简单的Mie散射模型来解释

Laser-Photophoresis is a promising technique to migrate and to separate microparticles in liquid media. However, the effect of photothermal conversion on the photophoretic behavior of photo-absorbing microparticles is still ambiguous. In this research project, we have made the following studies to elucidate the effect of photothermal effects on the laser-photophoretic migration of microparticles. 1. Laser Photophoretic Migration with Periodic Expansion-Contraction Motion of Photo-Absorbing Microemulsion Droplets in Water. : It was elucidated that the origin of the motion is photothermal conversion and the mechanism of the periodic expansion-contraction motion is consisted of three steps. 2. Temperature Distribution in the Laser-Irradiated Droplet in Water. : The temperature of the front-side of the irradiated droplet is higher than that of the back-side of the droplet. This temperature distribution results in the reverse photophoresis. 3. Separation of Blood Cells by Laser-Photophoresis. : We proposed the method for the photophoretic separation of red blood cells and white blood cells. 4. Formation and Trapping of Bubbles in the Organic Solvents. We found new phenomena that the laser induces the formation of bubble in organic solvents and the bubble can be trapped by the laser beam. 5. Photophoretic behaviors of water droplets and aqueous solution droplets in organic solvents. : It was found that water absorbs 1064 nm laser light and this causes complex photophoretic behavior of aqueous droplets in organic solvents. These behaviors cannot be explained by the simple Mie scattering model