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number of different substrates. Deposition techniques allow layers
to be built up that can create needed polarizing light orientation
properties, including building up quarter-wave plates. Experiments
have been made with polymers containing nanoparticles to create
a material that can polarize light. A variety of types of nanoparticle
materials and related size variations have been explored for use in
connection with polarized light applications. The rodlike structures
of carbon nanotubes offer possibilities here as well. Self-assembly
and self-alignment approaches have also been explored. Enhancements made possible via nanomaterials can potentially have a great
impact on the effectiveness of many devices that use polarized light
in one way or another.
Chromics
Chromogenic materials are broadly defined as materials that show
a large change in their optical properties when subject to a change
in their surrounding energy stimuli. Changes are caused by actions
at the molecular level and are normally completely reversible. They
are often called color-changing materials. Various kinds of lightrelated chromics—photochromics, thermochromics, and electrochromics—are of great fascination to designers and engineers. Their
interesting properties have caused them to be called smart materials
in that they intrinsically respond or change when subject to various
energy stimuli. They have found wide use in a variety of application
settings—architecture, consumer products, and industrial and scientific devices. However, not all types of these chromogenic materials
available today truly make use of nanomaterials or nanotechnologies as narrowly defined; sometimes reactions are fundamentally
chemical only or involve thin films that may be of nano thickness
but do not involve nanoparticles.
Photochromic materials passively change colors when subjected to
sunlight and are commonly found in many products, such as eyeglasses that change tints in the sun. Photochromic materials can
come in many forms—for example, glasses or polymers. A typical
photochromic film, for example, would change to transparent
blue tint when exposed to sunlight and result in a more or less
colorless form when there is no sunlight. The rate of color change
is generally slow, depending on the light intensity and length of
exposure.
Photochromic glass absorbs visible light and darkens when exposed
to ultraviolet light. When the light source is removed, the glass
fades. The behavior is reversible. One approach used to create this
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number of different substrates. Deposition techniques allow layers
to be built up that can create needed polarizing light orientation
properties, including building up quarter-wave plates. Experiments
have been made with polymers containing nanoparticles to create
a material that can polarize light. A variety of types of nanoparticle
materials and related size variations have been explored for use in
connection with polarized light applications. The rodlike structures
of carbon nanotubes offer possibilities here as well. Self-assembly
and self-alignment approaches have also been explored. Enhancements made possible via nanomaterials can potentially have a great
impact on the effectiveness of many devices that use polarized light
in one way or another.
Chromics
Chromogenic materials are broadly defined as materials that show
a large change in their optical properties when subject to a change
in their surrounding energy stimuli. Changes are caused by actions
at the molecular level and are normally completely reversible. They
are often called color-changing materials. Various kinds of lightrelated chromics—photochromics, thermochromics, and electrochromics—are of great fascination to designers and engineers. Their
interesting properties have caused them to be called smart materials
in that they intrinsically respond or change when subject to various
energy stimuli. They have found wide use in a variety of application
settings—architecture, consumer products, and industrial and scientific devices. However, not all types of these chromogenic materials
available today truly make use of nanomaterials or nanotechnologies as narrowly defined; sometimes reactions are fundamentally
chemical only or involve thin films that may be of nano thickness
but do not involve nanoparticles.
Photochromic materials passively change colors when subjected to
sunlight and are commonly found in many products, such as eyeglasses that change tints in the sun. Photochromic materials can
come in many forms—for example, glasses or polymers. A typical
photochromic film, for example, would change to transparent
blue tint when exposed to sunlight and result in a more or less
colorless form when there is no sunlight. The rate of color change
is generally slow, depending on the light intensity and length of
exposure.
Photochromic glass absorbs visible light and darkens when exposed
to ultraviolet light. When the light source is removed, the glass
fades. The behavior is reversible. One approach used to create this