understand the power of architectures, we first consider a neural
network. A neuron is a pretty dumb basic unit whose output is a simple
function of input. However, when neurons are connected together, as
shown below, they can perform complex tasks.
Typically, one neuron is connected to a few others and interact with each other electrochemically.
A smart thread is made by interconnecting many PODs. The diagram below shows a schematic representation of a smart thread made in a polymer optical fiber.
a neuron in the brain, each POD can communicate with all others
directly using light rather than using the slower electrochemical
neural process. Furthermore, each POD can be designed to act on a
different wavelength of light, making it possible for a subset of PODs
to communicate with other differently than with the rest of the
In addition to performing
logic operations using light, each POD acts as a sensor. Thus,
information about stress being applied to one POD can be quickly
transmitted to all other PODs. Furthermore, each POD acts as an
Thus, the collection of PODs on
a smart thread each can sense stress or temperature, perform
calculations, and provide actuation based on the information it
receives from all of the other PODs. Such smart thread, when woven into
a fabric, could yield an intelligence that is capable of morphing its
shape. The technological possibilities go well beyond what electronics
the idea of photomechanics has been around for over a century, both
scientific and technological progress has been hampered by the need for
In this decade, the group of
Professor Palffy-Muhoray has developed elastomeric materials that have
a more efficient photomechanical response, making interesting new
device demonstrations possible.
The photograph below
shows a tiny circular piece of an elastomeric material that has been
stressed into the shape of a potato chip.
Photo and diagram courtesy of Professor Peter Palffy-Muhoray
applying pulsed light to this structure, as diagramed above, the
material can be made to flap in a way that results in a swimming
motion. Indeed, Palffy-Muhoray and coworkers showed that such a
structure, floating on water, swam away from a pulsed laser beam. Once
the material enters a dark region, it stops swimming and remains in the
dark. Thus, the materials behave like roaches in search of the
protection of a shadow.
If such a material were made of
a smart fabric, the functionality would be much more sophisticated. The
examples here serve to illustrate the incredible potential of smart
 M. Camacho-Lopez, H.
Palffy-Muhoray, and M.
Shelley, "Fast liquid-crystal elastomer swims into the dark,"Nature Materials 3, 307 (2004).