Use of the Electrostatic Classification Method to Size 0.1 μm SRM Particles-A Feasibility Study

Area of Science:

• Aerosol science
• Metrology
• Materials science

Background:

• Accurate particle sizing is essential for developing Standard Reference Materials (SRMs).
• Electrostatic classification is a promising technique for precise particle characterization.

Purpose of the Study:

• To evaluate electrostatic classification for sizing 0.1 μm polystyrene latex (PSL) spheres.
• To assess its feasibility as a standard method for particle sizing in SRM development.

Main Methods:

• Experimental investigation of electrostatic classification performance.
• Measurement of mean electrical mobility for particle diameter calculation.
• Analysis of classifier transfer function, sensitivity, and repeatability.
• Sizing of NIST SRMs 1691 (0.269 μm) and 1690 (0.895 μm).

Main Results:

• Particle diameter uncertainty ranged from -3.3% to +3.0%.
• Key uncertainty sources include flow measurement, slip correction, and flow rate dependence.
• Classifier calibration achieved 0.1% accuracy for SRM sizes with a 1.9% adjustment to classification length.

Conclusions:

• Electrostatic classification demonstrates feasibility for standardizing 0.1 μm PSL sphere sizing.
• The method provides high accuracy suitable for Standard Reference Material development.
• Further refinement of classification length can enhance measurement precision.