Krishna H, Shirato N, Favazza C, Kalyanaraman R
Department of Physics, Washington University, St. Louis, MO 63130, USA.
Phys Chem Chem Phys. 2009 Oct 1;11(37):8136-43. doi: 10.1039/b906281p. Epub 2009 Jul 14.
Nanometre thick metallic liquid films on inert substrates can spontaneously dewet and self-organize into complex nanomorphologies and nanostructures with well-defined length scales. Nanosecond pulses of an ultraviolet laser can capture the dewetting evolution and ensuing nanomorphologies, as well as introduce dramatic changes to dewetting length scales due to the nanoscopic nature of film heating. Here, we show theoretically that the self-organization principle, based on equating the rate of transfer of thermodynamic free energy to rate of loss in liquid flow, accurately describes the spontaneous dewetting. Experimental measurements of laser dewetting of Ag and Co liquid films on SiO(2) substrates confirm this principle. This energy transfer approach could be useful for analyzing the behavior of nanomaterials and chemical processes in which spontaneous changes are important.
惰性衬底上的纳米厚金属液膜能够自发地去湿，并自组织成具有明确长度尺度的复杂纳米形态和纳米结构。紫外激光的纳秒脉冲可以捕捉去湿过程的演变及随之产生的纳米形态，并且由于薄膜加热的纳米尺度特性，还能使去湿长度尺度发生显著变化。在此，我们从理论上表明，基于将热力学自由能的转移速率与液体流动中的损失速率相等的自组织原理，能够准确描述自发去湿现象。对SiO₂ 衬底上的Ag和Co液膜进行激光去湿的实验测量证实了这一原理。这种能量转移方法可能有助于分析自发变化起重要作用的纳米材料行为和化学过程。
