Aligning Polymer Semiconductors by Painting
For some, brushstrokes would seem to only be of concern to painters and critics, but scientists are growing ever more interested in these patterns. The reason for the interest is that the force applied by the brush can make molecules align, including those in polymer semiconductors. Researchers at the University of Michigan have recently succeeded in making a polymer whose molecules can be aligned this way, which greatly increased it conductive capabilities.
Typically within polymers, the molecules are chaotically misaligned in every direction, which impairs the speed at which electrons can travel. Electrons moving along a molecule are like cars on a highway, but between molecules the movement is more like a city street; slower. By aligning the 'highways' the electrons can get where they need to go much faster, but achieving this alignment has been a challenge. The researchers eventually figured it out by designing a polymer made up of flat molecules that attract each other. To keep the molecules from attracting each other before being painted onto a surface, the researchers added arms to them, which are long enough to keep the molecules apart, and bulky enough to not bond with each other.
When tested the researchers found electrons were travelling 1000 times faster in the aligned direction, than when they cut across the brushstrokes. Semiconducting polymers are of great interest for the electronics industry as they can be manufactured much more cheaply than modern inorganic semiconductors.
Source: University of Michigan