Featured Research

from universities, journals, and other organizations

Detecting chemicals, measuring strain with a pencil and paper

Date:
January 22, 2014
Source:
Northwestern University
Summary:
A team of students has proven that pencils and regular office paper can be used to measure strain on an object and detect hazardous gases.

A pencil-drawn chemiresistor can detect the presence of hazardous gases.
Credit: Northwestern University

Sometimes solving a problem doesn't require a high-tech solution. Sometimes, you have to look no farther than your desktop.

Three students from Northwestern University's McCormick School of Engineering -- an undergraduate, a master's student, and their teaching assistant -- have proven that pencils and regular office paper can be used to create functional devices that can measure strain and detect hazardous chemical vapors.

A paper describing their findings, "Pencil Drawn Strain Gauges and Chemiresistors on Paper," was published January 22 in Scientific Reports, an open-access journal from the Nature Publishing Group.

The project originated in fall 2011 in McCormick's Introduction to Conducting Polymers course (MSE 337) during a discussion about the conductive properties of graphene, a one-atom thick layer of carbon that can be parsed from regular pencil lead. (A misnomer, pencil "lead" actually comprises graphite in a clay binder.)

"When you draw a line on a piece of paper, the graphite may shed numerous graphene sheets," said Jiaxing Huang, associate professor of materials science and engineering. "A student asked, 'Can we use that graphene for something?' That started an exploration of what pencil traces can do."

One team of students -- including lead authors Cheng-Wei Lin (MS materials science '13) and Zhibo Zhao (BS materials science '13) -- started by measuring the conductivity of a pencil trace on paper, then used the traces to create a rudimentary electrode. They learned that curling the paper in one direction increased the trace's conductivity by compressing the conductive graphene particles. Curling the paper in the other direction loosened the graphene network and decreased conductivity.

The students then turned to the traces of a bendable toy pencil. (These novelty pencils are flexible because the graphite is mixed not with clay, but with a polymer binder.) Again, conductivity could be increased and decreased by manipulating the paper, but the students found it also was affected by the presence of volatile chemical vapors, such as those from toxic industrial solvents.

When the chemical is present, the polymer binder absorbs the vapors and expands, pushing the graphene network apart and decreasing conductivity. The conductivity decreased the most in the presence of vapors that are more readily absorbed by the polymer binder.

These types of chemical sensor -- also called "chemiresistors" -- are key elements in "electronic noses" for detecting toxic chemical vapors. In creating chemiresistors, researchers often use more expensive materials, such as networks of carbon nanotubes or metal nanoparticles, and need to disperse them in polymer matrix to form a network.

"Now our students showed that this can be done simply with a pencil and paper -- and it works," Huang said. "This is a great example showing how curiosity leads to innovative work."

Other applications of the pencil-and-paper technology could be more unconventional. "It could help to inspire some new form of art," Huang said. "Perhaps one can make 'smart' and interactive drawings, in which the art itself is the circuitry and can respond to the environment."


Story Source:

The above story is based on materials provided by Northwestern University. Note: Materials may be edited for content and length.


Journal Reference:

  1. Cheng-Wei Lin, Zhibo Zhao, Jaemyung Kim, Jiaxing Huang. Pencil Drawn Strain Gauges and Chemiresistors on Paper. Scientific Reports, 2014; 4 DOI: 10.1038/srep03812

Cite This Page:

Northwestern University. "Detecting chemicals, measuring strain with a pencil and paper." ScienceDaily. ScienceDaily, 22 January 2014. <www.sciencedaily.com/releases/2014/01/140122202308.htm>.
Northwestern University. (2014, January 22). Detecting chemicals, measuring strain with a pencil and paper. ScienceDaily. Retrieved October 1, 2014 from www.sciencedaily.com/releases/2014/01/140122202308.htm
Northwestern University. "Detecting chemicals, measuring strain with a pencil and paper." ScienceDaily. www.sciencedaily.com/releases/2014/01/140122202308.htm (accessed October 1, 2014).

Share This



More Matter & Energy News

Wednesday, October 1, 2014

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

Japan Looks To Faster Future As Bullet Train Turns 50

Japan Looks To Faster Future As Bullet Train Turns 50

Newsy (Oct. 1, 2014) Japan's bullet train turns 50 Wednesday. Here's a look at how it's changed over half a century — and the changes it's inspired globally. Video provided by Newsy
Powered by NewsLook.com
US Police Put Body Cameras to the Test

US Police Put Body Cameras to the Test

AFP (Oct. 1, 2014) Police body cameras are gradually being rolled out across the US, with interest surging after the fatal police shooting in August of an unarmed black teenager. Duration: 02:18 Video provided by AFP
Powered by NewsLook.com
Raw: Japan Celebrates 'bullet Train' Anniversary

Raw: Japan Celebrates 'bullet Train' Anniversary

AP (Oct. 1, 2014) A ceremony marking 50 years since Japan launched its Shinkansen bullet train was held on Wednesday in Tokyo. The latest model can travel from Tokyo to Osaka, a distance of 319 miles, in two hours and 25 minutes. (Oct. 1) Video provided by AP
Powered by NewsLook.com
Robotic Hair Restoration

Robotic Hair Restoration

Ivanhoe (Oct. 1, 2014) A new robotic procedure is changing the way we transplant hair. The ARTAS robot leaves no linear scarring and provides more natural results. Video provided by Ivanhoe
Powered by NewsLook.com

Search ScienceDaily

Number of stories in archives: 140,361

Find with keyword(s):
Enter a keyword or phrase to search ScienceDaily for related topics and research stories.

Save/Print:
Share:

Breaking News:

Strange & Offbeat Stories


Space & Time

Matter & Energy

Computers & Math

In Other News

... from NewsDaily.com

Science News

Health News

Environment News

Technology News



Save/Print:
Share:

Free Subscriptions


Get the latest science news with ScienceDaily's free email newsletters, updated daily and weekly. Or view hourly updated newsfeeds in your RSS reader:

Get Social & Mobile


Keep up to date with the latest news from ScienceDaily via social networks and mobile apps:

Have Feedback?


Tell us what you think of ScienceDaily -- we welcome both positive and negative comments. Have any problems using the site? Questions?
Mobile: iPhone Android Web
Follow: Facebook Twitter Google+
Subscribe: RSS Feeds Email Newsletters
Latest Headlines Health & Medicine Mind & Brain Space & Time Matter & Energy Computers & Math Plants & Animals Earth & Climate Fossils & Ruins