could measure particle size and zeta potential. These are both liquid based methods

Sharon Stephen What are the critical features? i.e., what is the application for these particles?

Paul F Luckham, Thank you for the suggestion. I would like to know the exact names of technique liquid based for particle size determination

John Francis Miller, I would like to explore more on the plant synthesized Nanoparticle for its biological activities.

Sharon Stephen

Keep in liquid 'suspension'. Never dry. This will prevent the irreversible aggregation of nano (< 100 nm particles). Lots of liquid based routes. XRD can be carried out in liquid phase with appropriate holders. For particle size distribution dynamic light scattering (DLS). Crystallite (not particle) size by Williamson-Hall or Scherrer routes. Morphology and size and (essential) visualization of systems by electron microscopy. Single average particle size by peak in UV-VIS spectrum. And so on. Chapter by a criminal:

Characterization of Nanomaterials (January 2017) DOI: 10.1002/9783527800308.ch7 In book: Metrology and Standardization of Nanotechnology

Also look at the webinar (registration required) mentioned in:

https://www.researchgate.net/post/How_to_deagglomerate_the_dry_nano-particle_powder_for_DLS_measurements_How_to_use_a_suitable_surfactant_for_this_purpose

I repeat the quotations:

• 'I think dry nanotechnology is probably a dead-end' Rudy Rucker Transhumanity Magazine (August 2002).
• ‘If the particles are agglomerated and sub-micron it may be impossible to adequately disperse the particles……‘The energy barrier to redispersion is greater if the particles have been dried. Therefore the primary particles must remain dispersed in water….’ J H Adair, E. Suvaci, J Sindel, “Surface and Colloid Chemistry” Encyclopedia of materials: Science and Technology pp 8996 - 9006 Elsevier Science Ltd. 2001 ISBN 0-08-0431526

Several analytical techniques are available for the characterization of nanoparticles like zeta sizer/potential , XRD, SEM etc.

@ Alan F Rawle. Thank you for the suggestion. It would really help me.