X-PEEM Study on Surface Orientation of Stylized and Rubbed Polyimides.
X-ray photoelectron emission microscopy (X-PEEM) was used to study the surface orientation of stylized and rubbed polyimide thin films. Using soft X-rays produced by a synchrotron light source, this technique combines high spatial resolution imaging with near-edge X-ray absorption fine structure (NEXAFS) spectroscopy to yield information on the surface orientation of the films. Stylizing is an ideal model of the rubbing process since the local stress acting on the polyimide to orient the molecules can be calculated. The minimum normal stress necessary to orient the surface of BPDA-PDA films was found to be 45 MPa much lower than the bulk yield stress of 200-300 MPa. Studies of the polyimide films oriented by the conventional rubbing method showed lateral inhomogeneities in the orientation of the polymer at the surface.
Cossy-Favre
A
Advanced Light Source, Lawrence Berkeley National Laboratory, 1 Cyclotron Road, Berkeley, California 94720, Department of Polymer Science and Engineering, University of Massachusetts, Amherst, Massachusetts 01003, BHP Steel Institute, University of Wollongong, Wollongong NSW 2522, Australia, and Almaden Research Center, IBM Research Division, San Jose, California 95120.
Díaz
J
Liu
Y
Brown
HR
Samant
MG
Stöhr
J
Hanna
AJ
Anders
S
Russell
TP