Overview - ISO/TS 23151:2021 (cellulose nanocrystals particle size distribution)
ISO/TS 23151:2021 specifies methods to measure particle size distribution for cellulose nanocrystals (CNCs) using microscopy. The technical specification covers reproducible dispersion of CNCs (via ultrasonication), assessment of dispersions using dynamic light scattering (DLS), sample preparation for atomic force microscopy (AFM) and transmission electron microscopy (TEM), image acquisition, and image/data analysis. It supports consistent, comparable size characterization for CNCs produced by different processes and for surface‑modified materials.
Key topics and technical requirements
- Dispersion protocol
- Guidance on reproducible dispersion of dry CNCs using ultrasonication.
- Use of DLS to assess dispersion quality and to determine optimal sonication energy.
- Microscopy sample preparation
- Procedures for preparing samples for AFM and TEM to minimize artefacts and aggregation.
- Instrumentation and calibration
- Requirements for AFM and TEM instrumentation, accessories and microscope calibration to ensure traceable imaging.
- Data acquisition and image analysis
- Standardized image acquisition parameters, recommended analysis workflows to extract particle dimensions and length distributions.
- Data quality and reporting
- Assessment of data quality, fitting distribution models, and evaluation of measurement uncertainty.
- Content requirements for a complete test report covering sample, acquisition and analysis metadata.
- Definitions and scope
- Terminology aligned with ISO/TS 80004‑2; CNCs described as crystalline nanorods (typical cross‑section 3–50 nm; length 100 nm to several μm).
Applications and who should use this standard
ISO/TS 23151:2021 is relevant for:
- CNC producers and manufacturers - for product specification, quality control and batch consistency.
- Analytical and microscopy laboratories - to standardize AFM/TEM workflows and interlaboratory comparability.
- Researchers and R&D teams - characterizing CNC morphology, optimizing dispersion and studying structure–property relationships.
- Material formulators and end‑users (composites, coatings, personal care, rheology modifiers, optical films) - to verify input material properties affecting colloidal stability, viscosity and reinforcement performance.
- Regulatory and standards bodies - for consistent reporting and certification of nanocellulose materials.
Related standards
- ISO/TS 80004‑2 - Nanotechnologies vocabulary (nano‑objects terminology referenced).
- ISO 21363:2020 - Measurements of particle size and shape distributions by TEM (referenced for TEM measurement practices).
Keywords: ISO/TS 23151:2021, cellulose nanocrystals, particle size distribution, AFM, TEM, atomic force microscopy, transmission electron microscopy, dynamic light scattering, ultrasonication, sample preparation, image analysis.