Plastic That Changes Shape In Light 123
JLavezzo writes "Picture a flower that opens when facing the sunlight. In work that mimics that sensitivity to light, MIT Engineer Robert Langer and his German colleagues have created the first plastics that can be deformed and temporarily fixed into shape by light. This material could one day lead to medical devices that build themselves inside a patient's body, or door latches that can be opened with a flashlight. Additional commentary available at The Science Blog"
Heat and Artificial Muscles? (Score:5, Informative)
heat. The link below is to an article that shows a 30 gram weight
being lifted and lowered by a type of polymer know as nematic
elastomers.
http://www.sciam.com/article.cfm?articleID=0007
they also say in the above article(link) that, "..light can also induce
shape changes anywhere from 10 to 400 percent [in the polymer]."
However, it takes a hours for it to return to the original shape.
One of the best applications,in my opinion, for any fast-acting shape
changing polymer would be as artificial muscles. Not sure how
practical or easy that might be. You would have to get the temperature
range, where the shape changing takes place, down pretty low and find
a way to control it outside of the body's heat influence. I am sure
there are other problems as well.
clarfication (Score:5, Informative)
Re:Coming to a WalMart Near You! (Score:5, Informative)
Pasted from the straight dope [straightdope.com]
"Super glue, Krazy glue, Eastman 910 and similar glues are all a special type of glue called cyanoacrylates. Cyanoacrylates were invented in 1942 by Dr. Harry Coover of Kodak Laboratories during experiments to make a special extra-clear plastic suitable for gun sights. He found they weren't suitable for that purpose, so he set the formula aside. Six years later he pulled it out of the drawer thinking it might be useful as a new plastic for airplane canopies. Wrong again--but he did find that cyanoacrylates would glue together many materials with incredible strength and quick action, including two very expensive prisms when he tried to test the ocular qualities of the substance. Seeing possibilities for a new adhesive, Kodak developed "Eastman #910" (later "Eastman 910") a few years later as the first true "super glue." In a now-famous demonstration conducted in 1959, Dr. Coover displayed the strength of this new product on the early television show "I've Got a Secret," where he used a single drop placed between two steel cylinders to lift the host of the show, Garry Moore, completely off of the ground.
The use of cyanoacrylate glues in medicine was considered fairly early on. Eastman Kodak and Ethicon began studying whether the glues could be used to hold human tissue together for surgery. In 1964 Eastman submitted an application to use cyanoacrylate glues to seal wounds to the United States Food and Drug Administration (FDA). Soon afterward Dr. Coover's glue did find use in Vietnam--reportedly in 1966 cyanoacrylates were tested on-site by a specially trained surgical team, with impressive results."
Other related work (Score:5, Informative)
OSU had developed light-tunable plastic magnets [osu.edu]. Here the plastic material becomes 1.5 times more magnetic when blue light shines on it. Green light partially reverses that effect.
Another interesting work is from PSU on PLZT [psu.edu], this new material shows a large piezoelectric effect in response to near-ultraviolet light. Piezoelectric materials convert electricity into mechanical energy -- movement. When an electric current is run through piezoelectric ceramic, the ceramic changes size -- it shrinks or expands. Certain ferroelectric materials exhibit stronger photovoltaic (light into electricity) effects. Combining these ferroelectrics with piezoelectrics (electricity into motion), researchers created a single material that would convert light directly into motion.