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Combination of transmission electron and atomic force microscopy techniques to determine volume equivalent diameter of submicrometer particles
Author(s) -
Tumolva Laarnie,
Park JiYeon,
Park Kihong
Publication year - 2012
Publication title -
microscopy research and technique
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.536
H-Index - 118
eISSN - 1097-0029
pISSN - 1059-910X
DOI - 10.1002/jemt.21084
Subject(s) - transmission electron microscopy , particle (ecology) , volume (thermodynamics) , materials science , evaporation , analytical chemistry (journal) , ultrafine particle , atmospheric pressure , scanning electron microscope , particle size , electron microscope , nanotechnology , chemistry , composite material , optics , thermodynamics , chromatography , oceanography , physics , geology
Morphological properties of atmospheric particles are directly related to their residence time and transport behaviors, and their deposition patterns in human respiratory systems. The projected properties of particles measured by transmission electron microscopy (TEM) were combined with the particle height measured by atomic force microscopy (AFM) to determine volume equivalent diameter of submicrometer particles. For nonvolatile (refractory) laboratory‐generated spherical polystyrene latex and cubic NaCl particles, the measured volume equivalent diameters agreed well with the true values (within 4%). However, for nonrefractory (NH 4 ) 2 SO 4 particles, the measured volume equivalent diameter was much smaller than the true value due to evaporation of volatile species at low vacuum pressure and high electron‐beam intensity conditions in TEM, and deformation of particles in AFM. We observed that the volume equivalent diameter of 100 nm mobility‐classified atmospheric particles was 35 ± 5 nm, suggesting that these particles contain nonrefractory species, whereas that of 20 nm mobility‐classified atmospheric particles was found to be 19 ± 6 nm, suggesting that these particles were refractory and spherical. Microsc. Res. Tech., 2011. © 2011 Wiley‐Liss, Inc.