Dear all,
I would like to ask you for a method for measuring the core size and shape structure of iron oxide nanoparticles in high viscose liquid (except XRD) which cannot be evaporated. Also, I would like to know whether we can use TEM for liquid samples?
Many thanks in advance,
S.M.Ali Dadfar
Yes, DLS is an option but there are a few things to remember with viscous fluids - heat/thermal transfer is normally pretty poor so one may have to leave the sample in the cuvette in the instrument many minutes for thermal equilibration on the Peltier (if this is the temperature control device for the sample). Measurements at elevated temperature (to reduce the viscosity) may be helpful but as the diffusion coefficient is measured in DLS then this viscosity value needs to be accurately known as it has a direct relation to the derived hydrodynamic diameter. One can use a core-shell model in the software but there are plenty of assumptions that may or may not be valid.
Yes, you can dilute the respective nanoparticles in the respective dispersive medium just like 1 mg per ml then go for DLS. Meanwhile, you can TEM or HRTEM for shape and size measurement. You need to prepare your sample for TEM in powder by using a vacuum or freeze drier or you can drop a few drops of your nanoparticle solution on a copper/ silicon holder then put it in a dehumidifier for TEM
@ Alan F Rawle,
Thanks for your reply. Actually, I am interested in core size of nanoparticles NOT hydrodynamic diameter. Do you know other technologies for measuring the core size?
Many thanks in advance
@ Yaqub khan,
Thanks for your reply. Actually, the sample is in oil and can't evaporate it for TEM measurement.
S.M.Ali Dadfar
Ok no problem, maybe you can dry it up in a freeze drier or vacuum drier to evaporate the oil and then collect the particle. After collection, make them uniformly by mortar and then can go for SEM. In SEM maybe you can use it for shape and size measurement. For the TEM also the process will be the same but I think they use a resins/gum base for the powder samples.
S.M.Ali Dadfar
The particle is made up both of the core and the protective shell and I would argue you need both parts of the information to characterize the particle correctly. However, the core is electron rich and well visualized to electrons (where the protective coating isn't visible). I'd be using or trying cryo-EM to visualize such systems.
TEM or SEM will give you all about the particles in the fluid.
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