PDLC stands for Polymer Dispersed Liquid Crystal, a technology that first introduced and patented in 1984 in the US by Dr. James Ferguson. PDLC is a liquid crystal display cell in which a polymer network produced droplets or domains of liquid crystal. The optical properties of the cell depended on the alignment of the liquid crystals within each domain, with this alignment being determined by the balance of local alignment forces by the bounding polymer network, and any applied electric field. PDLC is switched between a milky white, scattering state and a transparent, non-scattering state.
There were two major material systems used for the fabrication of these systems. The first relied on a single-phase solution of the liquid crystal and the polymer precursor that was induced to phase-separate into a polymer network and liquid crystal domains.
Photopolymerization of reactive monomers and oligomers was by far the most popular pathway, given the versatility of photopolymerization chemistry and ease of processing. The vast majority of groups working on liquid crystal dispersion displays used phase separation methods to form their devices.
The other major approach towards dispersed liquid crystals used a water-based emulsion to form the composite film. An emulsion of liquid crystal droplets was dispersed into a water-based, film-forming polymer. This electro-optical “paint” was coated onto a conductive substrate, dried, and then laminated to a counter electrode.
PDLC technology enables to control the amount of light transmission through a film or glass surface. This can usually be controlled from a switch on the wall or a smartphone application, that determines the voltage that is applied through the surface.
PDLC technology laminated between two glass panes- Smart Glass, enhances traditional glass for Privacy on Demand applications and in many other ways. The internal plastic lamination in the glass, where the liquid crystals are scattered, provides enhanced protection to the glass, making it shatterproof.
The presence of crystal particles do block visibility and provide privacy. Additionally, the technology creates a reduction of the carbon footprint of the building thanks to the solar control, which reduces HVAC needs, both in summer and in winter.
PDLC glass can be used across sectors, including healthcare, hospitality and banking. In the medical sector, PDLC smart glass can replace unhygienic, traditional curtains that are a habitat for germs and bacteria.