Muruganathan Rm, Khattari Z, Fischer Th M
Department of Chemistry and Biochemistry, Florida State University, Tallahassee, Florida, USA.
J Phys Chem B. 2005 Nov 24;109(46):21772-8. doi: 10.1021/jp0537714.
We investigate the nonequilibrium behavior of two-dimensional gas bubbles in Langmuir monolayers. A cavitation bubble is induced in liquid expanded phase by locally heating a Langmuir monolayer with an IR-laser. At low IR-laser power the cavitation bubble is immersed in quiescent liquid expanded monolayer. At higher IR-laser power thermo capillary flow around the laser-induced cavitation bubble sets in. The thermo capillary flow is caused by a temperature dependence of the gas/liquid line tension. The slope of the line tension with temperature is determined by measuring the thermo capillary flow velocity. Thermodynamically stable satellite bubbles are generated by increasing the surface area of the monolayer. Those satellite bubbles collide with the cavitation bubble. Upon collision the satellite bubbles either coalesce with the cavitation bubble or slide past the cavitation bubble. Moreover we show that the satellite bubbles can also be produced by the emission from the laser-induced cavitation bubbles.
我们研究了朗缪尔单分子层中二维气泡的非平衡行为。通过用红外激光局部加热朗缪尔单分子层，在液体膨胀相中诱导出一个空化气泡。在低红外激光功率下，空化气泡浸没在静止的液体膨胀单分子层中。在较高的红外激光功率下，围绕激光诱导空化气泡的热毛细流开始出现。热毛细流是由气/液界面张力的温度依赖性引起的。通过测量热毛细流速度来确定界面张力随温度的斜率。通过增加单分子层的表面积产生热力学稳定的卫星气泡。这些卫星气泡与空化气泡碰撞。碰撞时，卫星气泡要么与空化气泡合并，要么从空化气泡旁滑过。此外，我们还表明，卫星气泡也可以由激光诱导空化气泡的发射产生。
