Mechanochromism, Shear Force Anisotropy, and Molecular Mechanics in Polydiacetylene Monolayers

Journal Article · Mon Aug 14 00:00:00 EDT 2000 · Tribology Letters

OSTI ID:761940

BURNS, ALAN R; CARPICK, R W; SASAKI, DARRYL Y; SHELNUTT, JOHN A; HADDAD, R

The authors use scanning probe microscopy to actuate and characterize the nanoscale mechanochromism of polydiacetylene monolayer on atomically-flat silicon oxide substrates. They find explicit evidence that the irreversible blue-to-red transformation is caused by shear forces exerted normal to the polydiacetylene polymer backbone. The anisotropic probe-induced transformation is characterized by a significant change in the tilt orientation of the side chains with respect to the surface normal. They also describe a new technique, based on shear force microscopy, that allows them to image friction anisotropy of polydiacetylene monolayer independent of scan direction. Finally, they discuss preliminary molecular mechanics modeling and electronic structure calculations that allow them to understand the correlation of mechanochromism with bond-angle changes in the conjugated polymer backbone.

• Research Organization: Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Sandia National Lab. (SNL-CA), Livermore, CA (United States)
• Sponsoring Organization: US Department of Energy (US)
• DOE Contract Number: AC04-94AL85000
• OSTI ID: 761940
• Report Number(s): SAND2000-2057J; TRN: AH200035%%162
• Journal Information: Tribology Letters, Other Information: Submitted to Tribology Letters; PBD: 14 Aug 2000
• Country of Publication: United States
• Language: English

Related Subjects

32 ENERGY CONSERVATION, CONSUMPTION, AND UTILIZATION
ANISOTROPY
BOND ANGLE
ELECTRONIC STRUCTURE
FRICTION
POLYMERS
SILICON OXIDES
SURFACE PROPERTIES
PHASE TRANSFORMATIONS
TRIBOLOGY
ORGANIC POLYMERS
ATOMIC FORCE MICROSCOPY
FRICTION FORCE MICROSCOPY
FRICTION ANISOTROPY
SHEAR FORCE MICROSCOPY
NANOTRIBOLOGYP
POLYDIACETYLENES
LB FILMS
MOLECULAR MECHANICS
CONJUGATED POLYMERS