ISO INTERNATIONAL STANDARD 19749 First edition 2021-07 Nanotechnologies Measurements of particle size and shape distributions by scanning electron microscopy Nanotechnologies - Détermination de la distribution de taille et de forme des particules par microscopie électronique a balayage Reference number IS0 19749:2021(E) ISO @IS02021 IS0 19749:2021(E) COPYRIGHT PROTECTED DOCUMENT @ iS0 2021 All rights reserved. Unless otherwise specified, or required in the context of its implementation, no part of this publication may be reproduced or utilized otherwise in any form or by any means, electronic or mechanical, including photocopying, or posting on the internet or an intranet, without prior written permission. Permission can be requested from either IsO at the address below or Iso's member body in the country of the requester. ISO copyright office CP 401 · Ch. de Blandonnet 8 CH-1214 Vernier, Geneva Phone: +41 22 749 0111 Email: [email protected] Website: www.iso.org Published in Switzerland i @ IS0 2021 - All rights reserved IS0 19749:2021(E) Contents Page Foreword .V Introduction. ..vi 1 Scope. .1 2 Normative references. .1 3 Terms and definitions .2 3.1 General terms. .2 3.2 Core terms: image analysis 4 3.3 Core terms: statistical symbols and definitions 4 3.4 Coreterms:measurandsanddescriptors .6 3.5 Core terms: metrology 8 3.6 Core terms: scanning electron microscopy 10 4 General principles. .11 4.1 SEM imaging. .11 4.2 SEM image-based particle size measurements .12 4.3 SEM image-based particle shape measurements .13 5 Sample preparation .13 5.1 Sample preparation fundamental information. 13 5.2 Generalrecommendations .14 5.3 Ensuring good sampling of powder or dispersion-in-liquid raw materials. 14 5.3.1 Powders. 14 5.3.2 Nanoparticle dispersions in liquids 15 5.4 Ensuring representative dispersion. 15 5.5 Nanoparticle deposition on a substrate 15 5.5.1 General 15 5.5.2 Nanoparticle deposition on wafers and chips of silicon or other materials 16 5.5.3 Nanoparticle deposition on TEM grids. 17 5.6 Number of samples to be prepared. 18 5.7 Number of particles to be measured for particle size determination 18 5.8 Number of particles to be measured for particle shape determination .19 6 Qualification of the SEM for nanoparticle measurements .19 7 Image acquisition .19 7.1 General. 19 7.2 Setting suitable image magnification and pixel resolution 23 8 Particle analysis 24 8.1 Particle analysis fundamental information .24 8.2 Individual particle analysis. 25 8.3 Automated particle analysis .25 8.4 Automated particle analysis procedure example 26 9 Data analysis .27 9.1 General. .27 9.2 Raw data screening: detecting touching particles, artefacts and contaminants 27 9.3 Fitting models to data 27 9.4 Assessmentofmeasurementuncertainty 27 9.4.1 General. 27 9.4.2 Example: Measurement uncertainty for particle size measurements 28 9.4.3 Bivariate analysis... .29 10 Reporting the results .29 Annex A (normative) Qualification of the SEM for nanoparticle measurements .31 Annex B (informative) Cross-sectional titanium dioxide samples preparation. .36 @ IS0 2021 - All rights reserved ii IS0 19749:2021(E) Annex C (informative) Case study on well-dispersed 60 nm size silicon dioxide nanoparticles....38 Annex D (informative) Case study on 4o nm size titanium dioxide nanoparticles ..46 Annex E (informative) Example for extracting particle size results of SEM-based nanoparticle measurements using ImageJ. ..55 Annex F (informative) Effects of some image acquisition parameters and thresholding methods on SEM particle size measurements .57 Annex G (informative) Example for reporting results of SEM-based nanoparticle measurements 61 Bibliography .71 iv @ IS0 2021 - All rights reserved IS0 19749:2021(E) Foreword IsO (the International Organization for Standardization) is a worldwide federation of national standards bodies (IsO member bodies). The work of preparing International Standards is normally carried out throughIsotechnicalcommittees.Eachmembe