Furthermore, the authors can use the AFM tip or a near field scanning optical microscope (NSOM) tip to locally convert the PDA from the blue form to the red form via applied stress. Measurements with the atomic force microscope (AFM) reveal strongly anisotropic friction properties that are correlated with the orientation of the conjugated polymer backbone orientation. By altering the head group functionality, the authors can choose between mono- and tri-layer PDA film structures. In this paper, the authors discuss the Langmuir deposition of ultrathin PDA films and the subsequent measurement of their structural, optical, and mechanical properties at the nanometer scale. This transition can be brought about by heat binding of specific biological targets and applied stress (mechanochromism), among others. In addition, the red form is highly fluorescent, while the blue form is not. A wide variety of PDA materials, including bulk crystals, thin more » films, and solutions, exhibit a chromatic transition involving a significant shift in absorption from low to high energy bands of the visible spectrum, thus the PDA appears to transform from a blue to a red color. (SNL-CA), Livermore, CA (United States) Sponsoring Org.: US Department of Energy (US) OSTI Identifier: 761940 Report Number(s): SAND2000-2057J TRN: AH200035%%162 DOE Contract Number: AC04-94AL85000 Resource Type: Journal Article Journal Name: Tribology Letters Additional Journal Information: Other Information: Submitted to Tribology Letters PBD: Country of Publication: United States Language: English Subject: 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 = -conjugated backbone. (SNL-NM), Albuquerque, NM (United States) Sandia National Lab. Authors: BURNS, ALAN R CARPICK, R W SASAKI, DARRYL Y SHELNUTT, JOHN A HADDAD, R Publication Date: Research Org.: Sandia National Lab.
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