The liquid crystals change their refractive index in relation to the isotropically transparent polymer in which they are immersed, thereby creating multiple step boundaries throughout the PDLC.
It is this change in refractive index at each boundary which causes light to change course. Since the PDLC material contains millions of liquid crystals, each with a boundary facing a slightly different way, the light is scattered in many directions.
The net effect is to hide whatever is behind the PDLC smart glass.
What is the structure of PDLC glass?
PDLC smart glass is composed of :
Outermost panels of normal float glass (or sometimes acrylic) sandwiched around:
Inner panels of optically clear PET plastic (polyethylene terephthalate), sandwiched around:
ITO (Indium Tin Oxide) which is a transparent conductor, sandwiched around:
a PDLC core comprised of liquid crystal droplets, suspended in a polymer.
What is smart glass/film?
Smart glass/film is a switchable light control glass that turns a transparent glass to opaque instantaneously and vice versa.
Which sectors are using PDLC glass?
Transportation
Architectural (residential and commercial)
Interior design
Retail advertising
Healthcare (i.e. hospitals and clinics, since the PDLC smart glass can replace unhygienic curtains and blinds which often carry microbes and germs, and this also improves air quality)
Banking, thanks to the privacy afforded to ATMs and as internal partitions
Hospitality, especially bathrooms, since more natural light can penetrate interior spaces lacking windows to the outside world.
Does PDLC smart glass conduct electricity?
No, the internal PDLC layer is plastic and does not conduct electricity, since it is electrically insulated. Rather, it behaves more like a capacitor, where the applied signal alternates between positive and negative voltages at the plates of the capacitor, causing an alternating electric field throughout the PDLC dielectric, which is what aligns the liquid crystals with the frequency of the signal (normally 50 Hz or 60 Hz).
Why does PDLC require a polymer?
The polymer allows the liquid crystals to be embedded into a film, which can then be sandwiched between panels of glass or plastic. The polymer has constant optical properties which do not vary across its structure, and hence is considered isotropic.
In contrast, the liquid crystal itself is anisotropic, since its optical characteristics are not constant across its structure, but rather can vary under application of an electric field.
