---
title: "Electric-Charged Nanoparticles Can Turn a Clear Window Into a Mirror"
description: "By running an electric current through gold nanoparticles, researchers from the Imperial College of London made a transparent surface reflective."
date: "2017-09-13"
modified: "2017-09-13"
authors:
  - name: "Patrick Caughill"
    link: "https://futurism.com/authors/patrickcaughill"
url: "https://futurism.com/electric-charged-nanoparticles-can-turn-a-clear-window-into-a-mirror"
categories:
  - "Science & Energy"
tags:
  - "materials science"
  - "Nanotechnology"
  - "smart windows"
---

# Electric-Charged Nanoparticles Can Turn a Clear Window Into a Mirror

![](<https://futurism.com/wp-content/uploads/2017/09/mirror-window-nano-3.png>)
*\<em\>Image: \<a href="http://www3.imperial.ac.uk/newsandeventspggrp/imperialcollege/newssummary/news_5-9-2017-11-56-31" target="\_blank"\>Imperial College London\</a\>\</em\>*

## Instant Mirror

Researchers from [Imperial College London](<http://www3.imperial.ac.uk/newsandeventspggrp/imperialcollege/newssummary/news_5-9-2017-11-56-31>) have developed a material that can turn a transparent surface into a reflective one when an electric current is applied. We've all seen, at least in movies, one way mirrors used in police stations and spooky houses; this technology takes that idea to new levels of complexity and sophistication.

The team used gold nanoparticles, which are thousands of times smaller than the width of a single human hair, and placed them between two liquids which do not mix. When voltage is applied, the nanoparticles self-assemble into a new configuration closely together, making the surface reflective. Without the voltage, they are spaced apart, and the surface reverts to being transparent.

https://www.youtube.com/watch?v=68J0yLvrvJE

“This voltage drives nanoparticles to an interface, where they congregate and form a mirror. When we switch the system to a different voltage, the particles move away from the interface and the mirror disappears,” explains Anthony Kucernak, a professor in Imperial’s Department of Chemistry, to *[Digital Trends](<https://www.digitaltrends.com/cool-tech/window-glass-mirror-nanoparticles/>).*

## More Than Mirrors

This new application could help us see a near-future of advanced window and mirror systems. Research has already developed smart windows with the ability to self-shade, helping to regulate the temperature of a building, saving on heating and cooling costs. Yet other windows are being developed to generate solar power, potentially turning [skyscrapers into solar farms](<https://futurism.com/smart-electricity-generating-windows-are-on-their-way>).

The Imperial College team is considering commercialization of their own smart window findings, but first want to work to increase the speed of the particles' response.

These window/mirror innovations may be exciting, but that's not the only potential application for this tech. [As *New Atlas* suggested](<http://newatlas.com/mirror-window-nanoparticle-material/51298/>), this process could be used to create tunable optical filters for telescopes to help us better understand the universe and to make chemical sensors more sensitive — in other words, providing a window through which we can better understand our world.

### Author social links  
[LinkedIn](<https://www.linkedin.com/in/patrick-caughill-74178a61>)