Every person who has ever gotten inside a car that’s been sitting in the sun for a period of time knows the annoying, dreaded pain that follows when they sit down on the hot car seat. It can be a similar annoyance when people spot others peering into their car windows. 

Although these two instances may seem unavoidable, Yingfei Jiang, a graduate student from Kent State’s Advanced Materials and Liquid Crystal Institute, believes he found a solution to solve both problems using smart glass technology.

Smart glass has been around for years. This technology can be used to make smart windows that either keep people from peering into cars or keep the sun from overheating car seats.

Smart glass works by changing its light transmission properties when energy is applied, Jiang said. This means that when applying voltage, light or heat, the glass changes from transparent to translucent or vice versa.

Jiang found a way to combine both smart glass features into one dual-mode, switchable smart window, so people don’t have to choose one or the other.

In his recently published research paper, “Dual-Mode Switchable Liquid Crystal Window,” Jiang and his colleagues discuss how this discovery came to be.

The key ingredient in the dual-mode switchable smart window is the liquid crystal and its two properties: dielectric and flexoelectric, Jiang said. 

“Everybody knows there are three states of nature: solid, like ice; liquid, like water; and gas, like water steam,” Jiang said. “Liquid crystals are basically another state, a fourth state, that is between liquid and solid.”

The liquid crystal has a rigid core, which represents its solid state, and a flexible tail, which represents its liquid state. This means the molecules have some orientation order and aren’t randomly distributed, Jiang said. 

Jiang’s research paper discusses the use of voltage he and his colleagues applied to the liquid crystal’s dielectric and flexoelectric properties and its effect on the window.

“In my paper, I reported the low frequency I used as 50 Hz [Hertz] and the high frequency I used as 1 kHz [kiloHertz],” Jiang said. “This basically means 50 Hz was used for the flexoelectric property, which is for the privacy mode. The 1 kHz is for the dielectric property, [which is] for the energy-flow control mode.” 

From this point, one can combine these two properties into a single device, which solves the dilemma of single-mode smart windows, he said.

Jiang’s research can improve not only the windows in automobiles, but also in architectural buildings, including homes, he said.  

Although this technology will be expensive to attain for the average person, Jiang said the benefits of a dual-mode switchable smart window will outweigh the cost.

Contact Becca Sagaris at [email protected].