hide
Free keywords:
-
Abstract:
In this paper, we study the formation of microbubbles upon the irradiation of an array of plasmonic Au nanoparticles with a laser in n-alkanes (CnH2n+2, with n = 5-10). Two different phases in the evolution of the bubbles can be distinguished. In the first phase, which occurs after a delay time tau(d) of about 100 mu s, an explosive microbubble is formed, reaching a diameter in the range from 10 to 100 mu m. The exact size of this explosive microbubble barely depends on the carbon chain length of the alkane but more so on the laser power P-I. With increasing laser power, the delay time prior to bubble nucleation as well as the size of the microbubble both decrease. In the second phase, which sets in right after the collapse of the explosive microbubble, a new bubble forms and starts growing due to the vaporization of the surrounding liquid, which is highly gas-rich. The final bubble size in this second phase strongly depends on the alkane chain length; namely, it increases with a decreasing number of carbon atoms. Our results have important implications for using plasmonic heating to control chemical reactions in organic solvents.
