Other Applications - Hierarchical Nanostructures for Energy Devices - page 279

d n 3 r 4 n g | 8

.

Figure 12.6 (a) Optical image of a PC substrate with hierarchical mPLR/NW arrays

on the surface, showing its mechanical flexibility. Contact angle meas-
urements for (b) planar PC substrate, (c) PCmPLR arrays, and (d)
hierarchical mPLR/NW structures. The length and pitch of mPLRs are
L mPLR ¼ 10 mm and P mPLR ¼ 6 mm. In all cases, the surface is coated with a
thin layer ( B 10 nm) of parylene-N by a gas deposition process.
Reproduced with permission from ref. 74.

12.2.4 Pool Boiling Enhancement
The large surface area of hierarchical nanostructures also can be used to
enhance heat transfer and pool boiling. As the technology in micro-
electronics design and manufacturing advances, the feature size in many
devices is getting smaller and smaller, leading to an explosive increase in
manufacturable integrated circuit (IC) chips thereby decreasing the price.
However, IC devices should be maintained at low temperature in order to
improve reliability and prevent premature failure by means of cooling, since
the semiconductor is vulnerable to heat. Due to the rising requirement of