Polymer, Fiber, Bionics - Inventions/Patents/Research

[Kammy]

Shape-Memory Polymers

'Retrospective Rubber' Remembers Its Old Identities

"ScienceDaily (Dec. 16, 2007) — Researchers at the University of Rochester have developed a shape-memory rubber that may enable applications as diverse as biomedical implants, conformal face-masks, self-sealing sutures, and "smart" labels.

The material, described in the journal Advanced Materials, forms a new class of shape-memory polymers, which are materials that can be stretched to a new shape and will stay in that form until heated, at which time they revert to their initial shape.

Unlike conventional shape-memory polymers, however, the new material is transparent, rubbery, and most importantly, engineers will be able to control the speed at which it returns to its original shape. Other shape memory polymers use crystallization to hold a temporary shape, which often makes them opaque, hard, and brittle in their frozen states, and this can limit their use.

The new rubber functions differently than conventional shape-memory materials by using "sticker groups"—hydrogen bonding groups that form temporary bonds. These sticker groups break and reform constantly.

"This polymer could be made into a thread that responds precisely to body temperature, tightening the sutures to the perfect pressure."

"At higher temperatures the material stretches like a rubber band, but, at lower temperatures, it stiffens up," says Mitchell Anthamatten, assistant professor of chemical engineering and inventor of the material.

Anthamatten is currently investigating how dyes diffuse through his networks.

One aspect of the clear rubber that surprised Anthamatten was how easy it is to make. "It's ridiculously simple," he says..."

[Kammy]

Shape-memory Polymers Designed For Biomedical Applications

"ScienceDaily (Jan. 10, 2008 ) — Researchers at the Georgia Institute of Technology are developing unique polymers, which change shape upon heating, to open blocked arteries, probe neurons in the brain and engineer a tougher spine.
These so-called shape-memory polymers can be temporarily stretched or compressed into forms several times larger or smaller than their final shape. Then heat, light or the local chemical environment triggers a transformation into their permanent shape.

"My focus has been to optimize these polymers for many different biomedical applications. My lab studies how altering the chemistry and structure of the polymers affects their chemical, biological and mechanical properties," said Ken Gall, a professor in the George W. Woodruff School of Mechanical Engineering and School of Materials Science and Engineering.

The mechanical properties of these polymers make them extremely attractive for many biomedical applications, according to Gall, who described his research in this area during two presentations at the Materials Research Society's fall meeting in November.

Engineers are always searching for materials that display unconventional properties able to satisfy the severe requirements for implantation in the body. Particular attention must be paid to the biofunctionality, biostability and biocompatibility of these materials, which come into contact with tissue and body fluids.

"You can tailor the polymer to moderate its strength, stiffness, stretchiness and expansion rate," noted Gall.

"We're looking for smart materials that can be synthesized in the size range of 100 microns -- similar to the size of a strand of hair -- and then be inserted into brain tissue," explained Gall."

[Kammy]

Scientists Demonstrate All-fiber Quantum Logic

“Such all fiber quantum information processing will likely have important applications in future quantum networks.

All-fiber quantum information processing could be used in less mature quantum technologies such as computing, communication and advanced measurement, as well as in the fundamental science of quantum optics."

[Kammy]

Nanoscience Study Shows That Quantum Dots 'Talk'

"ScienceDaily (Feb. 23, 2006 ) — Scientists who hope to use quantum dots as the building blocks for the next generation of computers have found a way to make these artificial atoms communicate.

Quantum dots could be injected into the patient, and a device containing more quantum dots could be used to show the position of dots under the skin.

“The idea is to make the (computing) process faster and smaller,” said Al-Ahmadi."

[Kammy]

Unexpected Behavior Of Quantum Dots When Combining To Form Molecules

"ScienceDaily (Apr. 4, 2009) — A study has demonstrated that the behaviour of quantum dots is different from that posited by atomic physics so far, and this is due to the spin of the electron."

Scientists Find Flaw In Quantum Dot Construction

The problem, they argued, happens during the creation of the type of quantum dots under study. Using a molecular beam epitaxy chamber, scientists spray paint a surface with atoms under high temperatures, creating an atomic coating. As more layers are added, the quantum dots bead up on the surface like droplets of water, Ulloa said. But a fine residue left behind on the surface that Ulloa calls the "wetting layer" can cause problems during experiments. When experimental scientists blasted the quantum dots with a beam of light in previous studies, the wetting layer caused interference, instead of allowing the light to enter the dot and trigger the quantum state, he explained.

Ulloa added. "It's one more step towards the holy grail of finding a better quantum bit, which hopefully will lead to a quantum computer," he said."

[Kammy]

Metal Rubber -- Chemists Create Self-assembling Conductive Rubber

**See Video.

"April 1, 2007 — Polymer chemists have created a flexible, indestructible material, called metal rubber, that can be heated, frozen, washed or doused with jet fuel, and still retain its electricity-conducting properties. To make metal rubber, chemists and engineers use a process called self-assembly. The material is repeatedly dipped into positively charged and negatively charged solutions. The positive and negative charges bond, forming layers that conduct electricity. Uses of metal rubber include bendy, electrically charged aircraft wings, artificial muscles and wearable computers."

[Kammy]

http://www.sciencedaily.com/images/2...0628183428.jpg

"The technology is a merger of two different chemical processes for growing polymer molecules: one grows tiny dots of polymer "seeds" on a flat surface, and the other grows vertical fibers out from the top of the seeds. The fibers grow until the scientists cut off the chemical reaction, forming a carpet of uniform height."

[Kammy]

Coats Of Cellulose From Bacteria Yield Greener, Stronger Natural Composites

"ScienceDaily (June 20, 2008 ) — Researchers in the United Kingdom report the first use of bacteria to deposit sticky coatings of cellulose on the surfaces of plant fibers, a process that may expand the use of natural fibers in renewable plastic composites used as strong, lightweight materials for cars, airplanes, and other products.

In the new study, Alexander Bismarck and colleagues point out that synthetic composite materials now in use are made from nonrenewable, petroleum sources which are becoming more expensive. These materials not only are difficult to break down, they also create environmental hazards when disposed."

Researchers report a new method of depositing
bacterial cellulose on plant fibers to enhance
durability and strength of composite materials.
(Credit: Courtesy of American Chemical Society)

[Kammy]

'Super Paper:' New Nanopaper More Break-resistant Than Cast Iron

"ScienceDaily (June 10, 2008 ) — Researchers in Sweden and Japan report development of a new type of paper that resists breaking when pulled almost as well as cast iron. The new material, called "cellulose nanopaper," is made of sub-microscopic particles of cellulose and may open the way for expanded use of paper as a construction material and in other applications, they suggest.

In the new study, Lars A. Berglund and colleagues note that cellulose -- a tough, widely available substance obtained from plants -- has potential as a strong, lightweight ingredient in composites and other materials in a wide range of products.

The study described a solution to this problem. It involves exposing wood pulp to certain chemicals to produce cellulose nanopaper. Their study found that its tensile strength -- a material's ability to resist pull before snapping -- exceeded that of cast iron."

Scientists report development of cellulose nanopaper,
a superstrong material that could be used in the
construction industry. Above is a cross-section
of a fracture surface of a cellulose nanofibril film.
(Credit: Courtesy of American Chemical Society)

[Kammy]

New Material Made From Paper Sludge Could Replace Plastic Packaging

"ScienceDaily (July 3, 2009 ) — Margarita Calafell, a researcher at the Department of Chemical Engineering of the UPC’s School of Industrial and Aeronautical Engineering of Terrassa (ETSEIAT), has developed a new material by applying a biotechnological treatment to paper sludge.

The new patented material has unique properties. It is low density, mouldable, fire resistant, impermeable, porous and highly resistant, and it may replace less environmentally friendly materials in many industry and production sectors.

Recycling paper to obtain more paper or cardboard has been a common process for many years. However, the production of a new, highly resistant, versatile and environmentally friendly material from the unwanted waste of this process is a completely new idea.

1 kg of paper, 1 kg of new material

This researcher has devised a new biotechnology method that she has used to modify the chemical and structural properties of the cellulose materials that are left over from the paper recycling process. Thus, she has created a new compact, mouldable, fire resistant, impermeable, strong, porous material that could, in many cases, replace materials that are not environmentally friendly or that are more expensive, such as plastics, wood derivatives or rubber.

However, Margarita Calafell insisted that the product of the new technique is not a kind of agglomerate, but a new material with unique, uniform properties that has yet to be named."