Prototype for low-energy consuming switchable smart windows developed

A novel technique for confining liquid crystals in an architecture known as hierarchical double networks of polymers have been developed, said the Ministry of Science and Technology on Thursday.

The technique can provide next-generation solutions for low-energy consumption on-demand switchable smart windows that operate between low and high transmittance, said the ministry.

"Interpenetrating polymer networks are soft matter systems that optimise different functionalities such as mechanical, optical, and electrical properties to provide novel solutions in engineering and biomedical applications. A specific class of these architectures, dubbed hierarchical double networks, that synergistically combine rigid and soft networks to realise thermal, electrical, and optical properties, is currently attracting a lot of attention," it noted.

The researchers have introduced a new level to this field by superimposing double networks atop liquid crystals. These networks are realised by two distinct, independently controlled, and on-demand stimuli: light and temperature.

While the former creates an orientationally self-assembled polymer network, the organogelation (converting to semi-solid material composed of gelling molecules organised in the presence of an appropriate organic solvent) of the second active component driven by temperature provides the second network which effectively traps the first one.

The overall result is a well-controlled porous hierarchical network that confines the liquid crystal while allowing it to be electrically switched between its direction-dependent states and governing the dynamics through the created virtual surfaces of polymeric and gel nature, said the ministry.

While exhibiting interesting physics in terms of the thermodynamic characteristics, these hierarchical physical networks also help in realising the next-generation solution for low-energy consuming privacy windows which are on-demand switchable between high and low haze states with very high spatial resolution achievable by present-day techniques of lithography, it added.