Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Learning how to erase electronic paper

30.03.2004


Developing electronic paper that can be written on and then erased with the touch of a button is a challenge. Sometimes the ink must adhere to the paper and other times bead up.



Getting it just right requires knowing how, on a molecular level, the liquid ink interacts with the solid paper.

Now Jeanne E. Pemberton has clarified why changing the electrical charge on electronic paper affects how well ink will stick.


The finding will further efforts to make a reusable tablet.

"The structure of water is different depending on whether the surface is charged or not," said Pemberton, the John and Helen Schaefer professor of chemistry at the University of Arizona in Tucson. "People have predicted this change, but no one has ever fully understood its molecular basis. Now we’ve seen it. This finding will help us predict how ink will interact with electronic paper."

Pemberton is the recipient of the American Chemical Society’s 2004 Award in Analytical Chemistry. At the symposium being given in her honor at the 227th ACS National Meeting in Anaheim, Calif., she’ll discuss her finding about electronic paper and other aspects of her work on liquid-solid interfaces. Her talk, "Chemical Measurement Science at the Interface," will be given on Monday, March 29 at 1:30 p.m. in Room 207D of the Anaheim Convention Center.

Pemberton’s specialty is studying what happens at the boundary between liquids and solids, an area called interfacial chemistry. She wants to know what’s going on right at the interface, the region where the layer of liquid just six or seven molecules deep interacts with the solid surface.

Knowing more about what happens at the interface will help with a variety of problems, including making better electronic paper, controlling corrosion, or figuring out whether some toxic chemical will stick to the soil or wash into the groundwater.

But studying the molecular interactions at the liquid-solid boundary is hard because the bulk of the liquid gets in the way, Pemberton said.

"Only sampling one-to-two nanometers of stuff is hard to do. That’s been the challenge," she said, adding that a nanometer is the length of only a couple of molecules.

So she figured out a way to create just the interface, without having the rest of the liquid present. She got the idea from noticing that if a solid object is dipped into water and removed, sometimes some of the water still clings to the object.

The method she and her research team developed, known as "emersion," applies a drop of liquid onto the end of a rotating cylinder. As the cylinder rotates, the liquid is spread into a thin film only a few molecules thick. Then the scientists use light beams of different energies to determine how the atoms in the liquid molecules are vibrating. The reseachers use that information to determine how the molecules in the boundary layer are different from molecules surrounded by lots of liquid.

"There are lots of other methods to study surfaces and interfaces and none has been as successful as emersion at understanding these solid-liquid interfaces at the molecular level," she said. Her research group is currently the only one in the world using the emersion method, which was developed in her laboratory.

So far, her team has used the method to figure out how water interacts with a solid that is chemically similar to electronic paper. Such paper is composed of a tiny checkerboard of cells, each of which can be individually charged.

If the cell has no charge, the water molecules are more attracted to each other than the paper, and they bead up. If the cell has an electrical charge, individual water molecules are attracted to the paper and spread out on it rather than sticking so strongly to one another.

Her finding will help make better electronic paper, she said, because knowing how the surface charge affects the structure of ink molecules at the interface is key to figuring out how to repeatedly write on and then completely erase the paper.

Providing a better understanding of a variety of liquid-solid interfaces is the goal of Pemberton’s research.

"You can’t have control at the subtle molecular level you need to make these technologies work without understanding the chemical nature of the interface," she said. "Mostly we don’t understand that yet."

Jeanne Pemberton | EurekAlert!
Further information:
http://www.arizona.edu/

More articles from Life Sciences:

nachricht During HIV infection, antibody can block B cells from fighting pathogens
14.08.2018 | NIH/National Institute of Allergy and Infectious Diseases

nachricht First study on physical properties of giant cancer cells may inform new treatments
14.08.2018 | Brown University

All articles from Life Sciences >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: New interactive machine learning tool makes car designs more aerodynamic

Scientists develop first tool to use machine learning methods to compute flow around interactively designable 3D objects. Tool will be presented at this year’s prestigious SIGGRAPH conference.

When engineers or designers want to test the aerodynamic properties of the newly designed shape of a car, airplane, or other object, they would normally model...

Im Focus: Robots as 'pump attendants': TU Graz develops robot-controlled rapid charging system for e-vehicles

Researchers from TU Graz and their industry partners have unveiled a world first: the prototype of a robot-controlled, high-speed combined charging system (CCS) for electric vehicles that enables series charging of cars in various parking positions.

Global demand for electric vehicles is forecast to rise sharply: by 2025, the number of new vehicle registrations is expected to reach 25 million per year....

Im Focus: The “TRiC” to folding actin

Proteins must be folded correctly to fulfill their molecular functions in cells. Molecular assistants called chaperones help proteins exploit their inbuilt folding potential and reach the correct three-dimensional structure. Researchers at the Max Planck Institute of Biochemistry (MPIB) have demonstrated that actin, the most abundant protein in higher developed cells, does not have the inbuilt potential to fold and instead requires special assistance to fold into its active state. The chaperone TRiC uses a previously undescribed mechanism to perform actin folding. The study was recently published in the journal Cell.

Actin is the most abundant protein in highly developed cells and has diverse functions in processes like cell stabilization, cell division and muscle...

Im Focus: Lining up surprising behaviors of superconductor with one of the world's strongest magnets

Scientists have discovered that the electrical resistance of a copper-oxide compound depends on the magnetic field in a very unusual way -- a finding that could help direct the search for materials that can perfectly conduct electricity at room temperatur

What happens when really powerful magnets--capable of producing magnetic fields nearly two million times stronger than Earth's--are applied to materials that...

Im Focus: World record: Fastest 3-D tomographic images at BESSY II

The quality of materials often depends on the manufacturing process. In casting and welding, for example, the rate at which melts solidify and the resulting microstructure of the alloy is important. With metallic foams as well, it depends on exactly how the foaming process takes place. To understand these processes fully requires fast sensing capability. The fastest 3D tomographic images to date have now been achieved at the BESSY II X-ray source operated by the Helmholtz-Zentrum Berlin.

Dr. Francisco Garcia-Moreno and his team have designed a turntable that rotates ultra-stably about its axis at a constant rotational speed. This really depends...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

VideoLinks
Industry & Economy
Event News

Within reach of the Universe

08.08.2018 | Event News

A journey through the history of microscopy – new exhibition opens at the MDC

27.07.2018 | Event News

2018 Work Research Conference

25.07.2018 | Event News

 
Latest News

'Building up' stretchable electronics to be as multipurpose as your smartphone

14.08.2018 | Information Technology

During HIV infection, antibody can block B cells from fighting pathogens

14.08.2018 | Life Sciences

First study on physical properties of giant cancer cells may inform new treatments

14.08.2018 | Life Sciences

VideoLinks
Science & Research
Overview of more VideoLinks >>>