nanoscience and society - IAP/TU Wien

476 Nanoenabled Products in Commerce
heat and sound insulating layers, increase of impermeability,
enhancement of quality and quality assurance,
and innovative and optimized process technology.
Nanoproducts in Architecture
Even in a conventional and rather conservative commercial
sector like architecture, nanoenabled products
offer high potential for the optimization of materials
and processes with respect to functionality, safety, design,
maintenance of value, profitability, and environmental
protection.
The spectrum of nanotechnology-driven improvements
already covers nearly all sectors of architecture.
Concerning structural work, nanotechnology allows for
optimization of construction materials containing cement-like
grout. Nanotechnology enables stability to be
increased by a factor of 10. The quality of insulating material
for outside facades and roofs can be significantly
enhanced. The contamination of facades and walls can be
efficiently suppressed using self-cleaning coatings based
on the lotus effect (e.g., a coating that mimics the way
lotus leaves repel water droplets and particles of dirt).
Nanoparticles allow for antimicrobial behavior. Coating
of glass can result in properties such as self-cleaning
and adjustable shading. The latter one allows the use of
the window as a sunscreen. Nanoparticles as additives in
polymers can be used as improved flame-retardant materials.
Nanotechnologically based coating techniques
also allow the production of scratch-resistant tiles.
Nanoproducts in Textiles and Optics
"Nanowhiskers" attached to individual cotton fibers
have led to new and improved properties ofbreathability,
stain resistance, water repellence, and wrinkle resistance.
The whiskers are hydrophobic, and water remains
on the top of the whiskers and above the surface of the
fabric. Titanium dioxide nanoparticles are applied for
ultraviolet (UV) protection of textiles.
Optical technologies are cross-sectional technologies
that contribute to technological advances in various
areas of commerce. The 21st century is, therefore,
also called the century of the photon (a photon is a
quantum oflight). Smart and reactive nanocolors focus
on enhancing the usability of products, such as the surface
of papers, packaging films, molded plastics, metals,
among others, are suited for designer products. These
smart colors, set up by chemically responsive optically
resonant multilayer nanostructures, incorporate one or
more of the following features: capabilities to respond
to an external stimulus or control, surfaces that indicate
the status of a material or product, or sensors or
actuators embedded within material or bonded to the
surface. The Austrian company Attophotonics, in collaboration
with Mondi, developed a variety of innovative
color materials with various functions (i.e., sensory
function, or reactive color) based on its nanocolors and
nanocoating technologies. Multi-nanolayers indicate,
for example, humidity levels and/or water contact via
a distinct reversible or irreversible color change coated
on paper, polymer, or metal films, as well as printed via
nanocolored inks. Potential applications have excited
interest in the industrial, commercial, medical, automotive,
military, and aerospace fields.
Foturan photosensitive glass is a photostructurable
glass ceramic manufactured by the Schott Glass Corporation.
Foturan is used as a substrate for micro-electro-mechanical
systems (MEMS). Microfabrication in
Foturan is achieved through patterning by a pulsed UV
laser, a follow-up heat treatment step, and chemical etching.
In Foturan, the exposed areas experience a selective
phase change in which the native amorphous glass
phase converts to a crystalline lithium silicate phase.
The degree and type of crystallization are both responsive
functions of the irradiation and thermal processing
procedures. Under high exposure, the crystallized areas
etch up to 30 times faster than the unexposed material
in high frequecy, with the etch rate varying with irradiation
dose. Because Foturan is transparent at visible
through infrared wavelengths, three-dimensional (3D)
direct-write exposure with a pulsed laser can detail
complex 3D structures within the Foturan material. Foturan
combines unique glass properties, such as transparency,
hardness, and chemical and thermal resistance,
with the opportunity to achieve very fine structures with
tight tolerances and high aspect ratio (hole depth/hole
width). Very small structures of 25 microns are possible
with a roughness of 1 micron.
Zerodur glass ceramic from Schott AG is made from
a mixture of crystallites, 30 nm to 50 nm in size, embedded
inside a glass matrix of lithium, aluminum,
and silicon oxides, and does not expand when subjected
to heat or shrink at low temperatures. Zerodur is
isotropic (i.e., invariant with respect to direction), homogeneous,
and can easily be polished. Zerodur glass
ceramics are applied in high-precision optics and in
the manufacturing of semiconductor chips. The semi-