Polyaniline Fibers, Films, and Powders: X-ray Studies of Crystallinity and Stress-Induced Preferred Orientation

• Published in: Macromolecules Vol. 27; no. 18; pp. 5094 - 5101
• Main Authors: Fischer, J. E, Zhu, Q, Tang, X, Scherr, E. M, MacDiarmid, A. G, Cajipe, V. B
• Format: Journal Article
• Language: English
• Published: Washington, DC American Chemical Society 01.08.1994
• Subjects: 360602 - Other Materials- Structure & Phase Studies; AMINES; Applied sciences; CRYSTAL STRUCTURE; Exact sciences and technology; FABRICATION; GRAIN ORIENTATION; HOT WORKING; MATERIALS SCIENCE; MATERIALS WORKING; MICROSTRUCTURE; ORGANIC COMPOUNDS; ORGANIC POLYMERS; ORIENTATION; Physicochemistry of polymers; POLYCYCLIC AROMATIC AMINES; POLYMERS; Properties and characterization; STRESSES; Structure, morphology and analysis; Nucleation; Crystal orientation; Film; Synthetic fiber; Crystallinity; Experimental study; Powder; Hot drawing; Oriented polymer; Amorphous orientation; Electrical conductor; Comparative study; Aniline polymer
• ISSN: 0024-9297; 1520-5835
• DOI: 10.1021/ma00096a036

Powder (hk0) and four-circle X-ray diffractometry are used to study the effects of hot-stretching on films and fibers of the emeralidine base form of polyaniline (EB-II). It is shown definitively that hot-stretching induces nucleation of new crystalline material rather than growth and/or orientation of pre-existing crystallites. The diffuse scattering from amorphous EB-II is dominated by short-range interchain correlations and develops preferred orientation in response to stretching but with a broader mosaic than the crystalline phase. For the maximally-stretched samples, the crystal fractions was determined by accounting for the different mosaic distributions of crystalline and amorphous phases, correcting for the mass of N-methylphenazolinium plasticizer and ruling out any significant contribution from NMP diffuse scattering to the amorphous EB-II profiles. Films stretched to L/L[sub 0] = 4.25 contain no more than 4% crystalline material while fibers with L/L[sub 0] = 4.5 are 24--30% crystalline. These fractional crystallinity values are significantly small than found for EB-II powder (60%). More importantly, these results have implications for models of electric properties which invoke interchain interactions.