IRG 1

Wisconsin MRSEC researchers have developed a coarse-graining technique called AniSOAP (for anisotropic smooth overlap of atomic potentials) that gives the beads shapes that reflect the shape of the molecules they represent. This simple idea – carefully implemented to be mathematically rigorous and account for how molecules typically interact – can used for high-accuracy coarse grained simulations or to understand materials behavior that depends on molecular shape or orientation. AniSOAP is also particularly useful for machine learning analysis of molecular behavior using simple, physically-interpretable algorithms, producing new insight for researchers.

Wisconsin MRSEC researchers have developed a new way to see how molecules fit together with an electron microscope. They used the method to see how molecules rearrange when an organic semiconductor is heated. A modest change in temperature creates significantly improved molecular alignment. The improved alignment is reflected in both larger aligned regions and straighter lines of molecules inside each region.

Physical vapor deposition (PVD) canproduce glassthinfilmswith preferred orientation to the molecules andhigherdensitythan ordinaryliquid-quenchedglass bytakingadvantageofthefastmovementoforiented moleculesonthe glasssurface.
Research supported by Wisconsin MRSEC have found a new way to control the structure and properties of these films by growing them on soft substrates. PVD on a soft substrate can produce glass thin films that are much more dense and stable than those deposited on rigid substrates. A film deposited on a soft substrate in 2 hours is equivalent to a film deposited extremely slowly on rigid substrates over ~3000 years.

Download PDF