including (i) optimization of density, (ii) extension to other polymer
systems, and (iii) a fundamental understanding of forces and
dynamics during bubble expansion, we remain very optimistic
about the potential of this approach for opening up applications
and new scientific directions. For example, nanostructure-BBFs
could be fabricated as reinforced nanocomposite films/coatings
which have visible/infrared absorption and fluorescence,47 NW/
NT-BBFs could yield flexible nanoelectronic systems integrating
high-performance FETs and chemical/biological sensors for
environmental and medical applications,39,48 and NW/NT-BBFs
might lead to ultra-large area high-density, flat panel displays.49
Moreover, by layering multiple nanostructure-BBFs or folding/
scrolling nanomaterials-BBFs, more complex three-dimensional
structures such as crossbars and hierarchically arranged nanoscale
building blocks21,50 might be fabricated to enable completely new
types of electronic/photonic systems in the future.
Acknowledgements
A. Cao and C. M. Lieber acknowledge funding support from the
US National Science Foundation (NSF) grant CMMI-0728197.
C. M. Lieber also acknowledges support of the Air Force Office
of Scientific Research and Samsung Electronics.