Thin polymer films exhibit glass transition temperatures (Tgs) that are depressed from the bulk material Tg because of increased degrees of chain motion. Using such films as gate dielectrics in organic thin-film transistors provides a sensitive new probe of polymer surface motional characteristics at the buried semiconductor-dielectric interface.
Scientists from UCSB's Materials Research Laboratory (MRL) and the Nestle Research Center (NRC), Lausanne, Switzerland have resolved a long-standing problem in the self-assembly behavior of lipid molecules in water.
Poly(ethylene terephthalate) (PET), a widely used engineering thermoplastic for carpet, clothing (fibers), tire cords, soda bottles and other containers, film, automotive, electronics, displays etc., will contribute several billion pounds of waste to landfills this year alone! According to the American Plastics Council, PET packaging was originally used for soft drinks, but packing applications today include other beverages such as water, juice, beer, in addition to other foods such as peanut butter and ketchup and a variety of other household products.
Fundamental MRSEC research often leads to new technologies that in turn create innovative start-up companies. QD Vision and Luminus Devices are two exciting examples of this process. In both cases, MRSEC-supported research at MIT helped to develop the basic platform for these new technologies.
At low temperatures, the electrons in most layered transition-metal chalcogenides undergo a phase transition into an interesting, highly-ordered state called the charge-density-wave (CDW), in which the electron density spontaneously acquires a weak, periodic spatial modulation. In a small subset of materials, the CDW state is destroyed and replaced by the superconducting state.
PCCM researchers have discovered a new method for making gratings: by prying apart two rigid plates that sandwich a thin, glassy polymeric film. The process fractures the film into complementary sets of ridges on each plate, with the ridges on one corresponding to the valleys on the other. The technique produces patterns with periodic spacing from 120 nm to 200 Â’µm, and the period simply scales as four times the film thickness, regardless of the molecular weight or chemical composition of the glassy polymer.
Electronic transport through a junction formed between silicon (Si), a monolayer of alkyl chains (C14H29) self-assembled on Si, and a metal (M) is dominated by thermionic emission above the semiconductor barrier and tunneling through the insulating molecular layer [1].
While many approaches have been developed over the years to transfer patterns onto flat surfaces, faithfully transferring patterns onto curves substrates remains a major obstacle to the development of large-area electronics. Recently, PCCM researchers have successfully patterned domed polyester substrates with metal stripes (gold, silver, etc.). They employed a soft, pre-patterned elastomeric stamp coated with a thin layer of metal by electron-beam evaporation, bent into a complementary hemisphere.