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Direct probing of solvent‐induced charge degradation in polypropylene electret fibres via electrostatic force microscopy
Author(s) -
KIM J.,
JASPER W.,
HINESTROZA J.
Publication year - 2007
Publication title -
journal of microscopy
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.569
H-Index - 111
eISSN - 1365-2818
pISSN - 0022-2720
DOI - 10.1111/j.1365-2818.2007.01716.x
Subject(s) - electret , electrostatic force microscope , materials science , cantilever , atomic force acoustic microscopy , non contact atomic force microscopy , polypropylene , piezoelectricity , capacitance , microscopy , analytical chemistry (journal) , voltage , electrostatics , kelvin probe force microscope , composite material , molecular physics , atomic force microscopy , chemistry , optics , nanotechnology , magnetic force microscope , electrode , electrical engineering , physics , chromatography , magnetization , quantum mechanics , magnetic field , engineering
Summary Electrostatic force microscopy was used to directly probe solvent‐induced charge degradation in electret filter media. Electrostatic force gradient images of individual polypropylene electret fibres were used to quantify the extent of charge degradation caused by the immersion of the fibres into isopropanol. Electrostatic force gradient images were obtained by monitoring the shifts in phase and frequency between the oscillations of the biased atomic force microscopy (AFM) cantilever and those of the piezoelectric driver. Electrostatic force microscopy measurements were performed using non‐contact scans at a constant tip‐sample separation of 75 nm with varied bias voltages applied to the cantilever. Mathematical expressions, based on the capacitance of the tip‐sample system, were used to model the phase and frequency shifts as functions of the applied bias voltage to the tip and the offset voltage due to the fibre's charge. Quantitative agreement between the experimental data and the simplified model was observed.