ISO/TS 23151:2021
(Main)Nanotechnologies — Particle size distribution for cellulose nanocrystals
Nanotechnologies — Particle size distribution for cellulose nanocrystals
This document describes methods for the measurement of particle size distributions for cellulose nanocrystals using atomic force microscopy and transmission electron microscopy. The document provides a protocol for the reproducible dispersion of the material using ultrasonication, as assessed using dynamic light scattering. Sample preparation for microscopy, image acquisition and data analysis are included.
Nanotechnologies — Distribution en taille des particules pour les nanocristaux de cellulose
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TECHNICAL ISO/TS
SPECIFICATION 23151
First edition
2021-09
Nanotechnologies — Particle size
distribution for cellulose nanocrystals
Nanotechnologies — Distribution en taille des particules pour les
nanocristaux de cellulose
Reference number
© ISO 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 01 11
Email: copyright@iso.org
Website: www.iso.org
Published in Switzerland
ii
Contents Page
Foreword .iv
Introduction .v
1 Scope . 1
2 Normative references . 1
3 Terms and definitions . 1
4 Abbreviated terms . 2
5 Dispersion of CNCs .2
5.1 General considerations. 2
5.2 Dispersion of CNCs by sonication . 3
5.3 Dynamic light scattering assessment of dispersions . 4
5.4 Determination of optimal sonication energy . 5
6 Sample preparation for microscopy .5
6.1 General considerations. 5
6.2 AFM sample preparation . 6
6.3 TEM sample preparation . 6
7 Atomic force microscopy . 6
7.1 General . 6
7.2 Instrumentation and accessories . 7
7.3 Microscope calibration . 7
7.4 Data acquisition . 7
7.5 Image analysis. 8
8 Transmission electron microscopy . 8
8.1 General . 8
8.2 Instrumentation and accessories . 9
8.3 Microscope calibration . 9
8.4 Data acquisition . 9
8.5 Image analysis. 9
9 Data analysis .10
9.1 General . 10
9.2 Assessment of data quality . 10
9.3 Fitting distribution models to data . 10
9.4 Measurement uncertainty . 11
10 Test report .12
10.1 Atomic force microscopy . 12
10.1.1 General information .12
10.1.2 Sample. 12
10.1.3 Data acquisition . . .12
10.1.4 Image analysis . 13
10.2 Transmission electron microscopy . 13
10.2.1 General information .13
10.2.2 Sample. 13
10.2.3 Data acquisition . . .13
10.2.4 Image analysis . 14
Annex A (informative) Assessment of CNC dispersions .15
Annex B (informative) Assessment of applied imaging force .16
Annex C (informative) Interlaboratory comparison results: AFM .18
Annex D (informative) Interlaboratory comparison results: TEM .25
Bibliography .34
iii
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
through ISO technical committees. Each member body interested in a subject for which a technical
committee has been established has the right to be represented on that committee. International
organizations, governmental and non-governmental, in liaison with ISO, also take part in the work.
ISO collaborates closely with the International Electrotechnical Commission (IEC) on all matters of
electrotechnical standardization.
The procedures used to develop this document and those intended for its further maintenance are
described in the ISO/IEC Directives, Part 1. In particular, the different approval criteria needed for the
different types of ISO documents should be noted. This document was drafted in accordance with the
editorial rules of the ISO/IEC Directives, Part 2 (see www.iso.org/directives).
Attention is drawn to the possibility that some of the elements of this document may be the subject of
patent rights. ISO shall not be held responsible for identifying any or all such patent rights. Details of
any patent rights identified during the development of the document will be in the Introduction and/or
on the ISO list of patent declarations received (see www.iso.org/patents).
Any trade name used in this document is information given for the convenience of users and does not
constitute an endorsement.
For an explanation of the voluntary nature of standards, the meaning of ISO specific terms and
expressions related to conformity assessment, as well as information about ISO's adherence to
the World Trade Organization (WTO) principles in the Technical Barriers to Trade (TBT), see
www.iso.org/iso/foreword.html.
This document was prepared by Technical Committee ISO/TC 229, Nanotechnologies.
Any feedback or questions on this document should be directed to the user’s national standards body. A
complete listing of these bodies can be found at www.iso.org/members.html and www.iec.ch/national-
committees.
iv
Introduction
Cellulose nanomaterials, including cellulose nanocrystals (CNCs) and cellulose nanofibrils, are
anticipated to have significant commercial impact. Cellulose nanocrystals are produced from naturally
occurring cellulose, primarily from wood pulps and annual plants, by acid hydrolysis. Their production
from readily available cellulose sources makes them a candidate for use as a potentially non-toxic,
biodegradable and sustainable nanomaterial. The recent demonstration of the feasibility of large-scale
CNC production and the availability of infrastructure for harvesting raw materials will facilitate their
commercial development. CNCs and cellulose nanofibrils are produced in a number of countries on pilot,
pre-commercial or commercial scales. Estimates of the market potential for cellulosic nanomaterials
are as high as 35 million metric tons annually, depending on the predicted applications and the
[10],[11]
estimated market penetration . Standards for characterization of CNCs are required for material
certification to facilitate sustained commercial and applications development.
Cellulose nanocrystals have high crystallinity and are nanorods with high aspect ratio, surface area
and mechanical strength. They assemble to give a chiral nematic phase with unique optical properties
and their surface chemistry can be modified to ensure colloidal stability in water and to facilitate
dispersion in a variety of matrices. These properties, plus their biocompatibility, low cost and minimal
toxicity, enable many potential applications. Industrial producers are working with receptor industries
in various application areas, including nanocomposite materials, health and personal care products,
paints, adhesives and thin films, rheology modifiers and optical films and devices. Standardization
activities within ISO/TC 229 and ISO/TC 6 have focused on nomenclature and terminology,
characterization methods in general and specific methods for determining surface functional groups,
metal ion and dry ash content. Particle size distribution is also a key property for CNC characterization.
Particle morp
...
TECHNICAL ISO/TS
SPECIFICATION 23151
First edition
2021-09
Nanotechnologies — Particle size
distribution for cellulose nanocrystals
Nanotechnologies — Distribution en taille des particules pour les
nanocristaux de cellulose
Reference number
© ISO 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 01 11
Email: copyright@iso.org
Website: www.iso.org
Published in Switzerland
ii
Contents Page
Foreword .iv
Introduction .v
1 Scope . 1
2 Normative references . 1
3 Terms and definitions . 1
4 Abbreviated terms . 2
5 Dispersion of CNCs .2
5.1 General considerations. 2
5.2 Dispersion of CNCs by sonication . 3
5.3 Dynamic light scattering assessment of dispersions . 4
5.4 Determination of optimal sonication energy . 5
6 Sample preparation for microscopy .5
6.1 General considerations. 5
6.2 AFM sample preparation . 6
6.3 TEM sample preparation . 6
7 Atomic force microscopy . 6
7.1 General . 6
7.2 Instrumentation and accessories . 7
7.3 Microscope calibration . 7
7.4 Data acquisition . 7
7.5 Image analysis. 8
8 Transmission electron microscopy . 8
8.1 General . 8
8.2 Instrumentation and accessories . 9
8.3 Microscope calibration . 9
8.4 Data acquisition . 9
8.5 Image analysis. 9
9 Data analysis .10
9.1 General . 10
9.2 Assessment of data quality . 10
9.3 Fitting distribution models to data . 10
9.4 Measurement uncertainty . 11
10 Test report .12
10.1 Atomic force microscopy . 12
10.1.1 General information .12
10.1.2 Sample. 12
10.1.3 Data acquisition . . .12
10.1.4 Image analysis . 13
10.2 Transmission electron microscopy . 13
10.2.1 General information .13
10.2.2 Sample. 13
10.2.3 Data acquisition . . .13
10.2.4 Image analysis . 14
Annex A (informative) Assessment of CNC dispersions .15
Annex B (informative) Assessment of applied imaging force .16
Annex C (informative) Interlaboratory comparison results: AFM .18
Annex D (informative) Interlaboratory comparison results: TEM .25
Bibliography .34
iii
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
through ISO technical committees. Each member body interested in a subject for which a technical
committee has been established has the right to be represented on that committee. International
organizations, governmental and non-governmental, in liaison with ISO, also take part in the work.
ISO collaborates closely with the International Electrotechnical Commission (IEC) on all matters of
electrotechnical standardization.
The procedures used to develop this document and those intended for its further maintenance are
described in the ISO/IEC Directives, Part 1. In particular, the different approval criteria needed for the
different types of ISO documents should be noted. This document was drafted in accordance with the
editorial rules of the ISO/IEC Directives, Part 2 (see www.iso.org/directives).
Attention is drawn to the possibility that some of the elements of this document may be the subject of
patent rights. ISO shall not be held responsible for identifying any or all such patent rights. Details of
any patent rights identified during the development of the document will be in the Introduction and/or
on the ISO list of patent declarations received (see www.iso.org/patents).
Any trade name used in this document is information given for the convenience of users and does not
constitute an endorsement.
For an explanation of the voluntary nature of standards, the meaning of ISO specific terms and
expressions related to conformity assessment, as well as information about ISO's adherence to
the World Trade Organization (WTO) principles in the Technical Barriers to Trade (TBT), see
www.iso.org/iso/foreword.html.
This document was prepared by Technical Committee ISO/TC 229, Nanotechnologies.
Any feedback or questions on this document should be directed to the user’s national standards body. A
complete listing of these bodies can be found at www.iso.org/members.html and www.iec.ch/national-
committees.
iv
Introduction
Cellulose nanomaterials, including cellulose nanocrystals (CNCs) and cellulose nanofibrils, are
anticipated to have significant commercial impact. Cellulose nanocrystals are produced from naturally
occurring cellulose, primarily from wood pulps and annual plants, by acid hydrolysis. Their production
from readily available cellulose sources makes them a candidate for use as a potentially non-toxic,
biodegradable and sustainable nanomaterial. The recent demonstration of the feasibility of large-scale
CNC production and the availability of infrastructure for harvesting raw materials will facilitate their
commercial development. CNCs and cellulose nanofibrils are produced in a number of countries on pilot,
pre-commercial or commercial scales. Estimates of the market potential for cellulosic nanomaterials
are as high as 35 million metric tons annually, depending on the predicted applications and the
[10],[11]
estimated market penetration . Standards for characterization of CNCs are required for material
certification to facilitate sustained commercial and applications development.
Cellulose nanocrystals have high crystallinity and are nanorods with high aspect ratio, surface area
and mechanical strength. They assemble to give a chiral nematic phase with unique optical properties
and their surface chemistry can be modified to ensure colloidal stability in water and to facilitate
dispersion in a variety of matrices. These properties, plus their biocompatibility, low cost and minimal
toxicity, enable many potential applications. Industrial producers are working with receptor industries
in various application areas, including nanocomposite materials, health and personal care products,
paints, adhesives and thin films, rheology modifiers and optical films and devices. Standardization
activities within ISO/TC 229 and ISO/TC 6 have focused on nomenclature and terminology,
characterization methods in general and specific methods for determining surface functional groups,
metal ion and dry ash content. Particle size distribution is also a key property for CNC characterization.
Particle morp
...
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