Technology, properties and applications
In brief
- Technology: Liquid crystals in polymer matrix - PDLC film with light-scattering or light-transmitting effect.
- Switchable transparency: Can be switched between opaque and transparent by electrical voltage.
- Applications: Architecture, vehicles, medical technology, advertising.
- Advantages & limitations: Noiseless, retrofittable, but slightly cloudy transparency and not UV-resistant.
⏱ Estimated reading time: 3 minutes
PDLC stands for "Polymer Dispersed Liquid Crystal" and describes an electrochromic technology based on the dispersion of liquid crystals in a polymer. This technology makes it possible to produce materials that can be switched between a transparent and a light-diffusing (milky) state. PDLC is widely used in particular for so-called "smart windows" or "smart glass".
A PDLC film typically consists of two transparent substrates, such as glass or plastic film, between which a layer of polymer matrix is embedded in which microscopically small liquid crystal droplets are dispersed. This layer is usually only a few micrometers thick. In the de-energized state, the liquid crystals are disordered, causing incident light to be scattered and the film to appear opaque. If an electrical voltage is applied, the liquid crystals align themselves along the electrical field, the light can pass through almost unhindered and the film becomes transparent.
Technical characteristics of PDLC
- Switching voltage: 30 - 100 V AC
- Response time: 10 - 100 ms
- Light transmission: up to 85 % (transparent)
- Power consumption: approx. 3 - 6 W/m² when switched on
- Operating temperature range: -20 to +60 °C
The key advantages of PDLC include
- Switchability between transparent and opaque
- Privacy protection at the touch of a button
- Blocking of UV and IR radiation
- No mechanical components: noiseless and low-maintenance
- Can be retrofitted into existing glazing systems
PDLC technology can be used in numerous areas. In architecture, the films are used as switchable glazing in conference rooms, partition walls in bathrooms or façade glazing. They can also be used as rear projection screens for projectors. In vehicle construction, they are used as partition panes or privacy windows. PDLC is also widely used in medical technology, for example in treatment rooms, as well as in design and advertising (e.g. as projection surfaces or interactive displays). The cost of PDLC films has fallen significantly in recent years.
However, there are also limitations: The maximum transparency when switched on is not comparable with conventional glass, as a slight gray haze remains. UV exposure can lead to degradation of the PDLC layer in the long term.
Conclusion
PDLC is a pioneering technology for the realization of switchable glazing. It offers flexible control options for light transmission and privacy and is increasingly being used in architecture and vehicle construction, even if technical and economic challenges remain.
