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A surface characterisation and microstructural study by scanning electron microscopy of the N-methyl-n-alkylpyrrolidinium tetrafluoroborate organic salts

journal contribution
posted on 01.01.2003, 00:00 authored by Jim Efthimiadis, Maria ForsythMaria Forsyth, D MacFarlane
A microstructural characterisation of the family of N-methyl-N-alkylpyrrolidinium tetrafluoroborate organic salts was carried out by observation of powder surface morphologies with the aim of extending the microstructure-property correlation. Inherent difficulties limiting extensive studies of organic solids by SEM, including volatility under vacuum, charging due to electron beam irradiation, and air-sensitivity were overcome with the use of a Field Emission SEM and cryostage attachment. This technique, providing considerable improvements in image quality at low accelerating voltages, enabled direct observation of complex microstructural features in samples exhibiting high temperature plastic crystalline phases (N,N-dimethylpyrrolidinium tetrafluoroborate [P11BF4]; N-methyl-N-ethylpyrrolidinium tetrafluoroborate [P12BF4]; N-methyl-N-propylpyrrolidinium tetrafluoroborate [P13BF4]). Extensive lattice imperfections including grain boundaries, slip planes and dislocation pits were observed within particles of approximately 200 mgrm diameter. The N-methyl-N-butylpyrrolidinium tetrafluoroborate (P14BF4) sample in this series revealed columnar single crystals with high aspect ratios. The origin of plastic flow properties is discussed using single crystal and polycrystalline slip observations and a relationship proposed between defect characteristics and transport properties.

History

Journal

Journal of materials science

Volume

38

Issue

15

Pagination

3293 - 3301

Publisher

Springer

Location

New York, N.Y.

ISSN

0022-2461

eISSN

1573-4803

Language

eng

Publication classification

C1.1 Refereed article in a scholarly journal

Copyright notice

2003, Kluwer Academic Publishers