My goal is to load up to 20-30% of nanoparticles while maintaining the transparency. These nanoparticles are made using solid state reaction at 1000C.
with 20 - 30% loading, I assume you will not achieve to keep the transparency you want. Either, your "nanoparticles" are not really nano-sized, but > 1 µm, then you can load that much, but then the particles will make the system hazy or even non-transparent, or you have nice nano-particles (maybe 100 nm size), then you will not be able to load that much without losing transparency (and many other properties).
you can find a lot about this in my RG page
I Think it mainly depends on band gap energy of your nanomaterials. if your nanoparticle is not absorbing visible light ( it means wide band gap particles), Definitely you will get the transparency. But I dont know for low band gap nanoparticles
I disagree. To achieve transparency, you need small particle size and good dispersion. "transparency" does not necessarily mean "colourless" (you can get transparent green or blue colour, what's wrong with that?).
But what I want to focus on is: only if you can combine havng a small particle size (well less than 1 µm) and optimal dispersion, only then the system can be transparent - but this, you can never have with 20 - 30 % loading.
Dear Bernhard Wessling,
suppose If we are loading transparent nanoparticles (less than 1 µm size) with transparent polymer system, what is the appropriate loading % to maintain transparancy in polymer matrix and what is the reason for getting non transparancy if we exceed that %?
hard to say as I don't know what material you are using (surface tension? particle size = specific surface?).
You may want to look into these 2 articles:
https://www.researchgate.net/publication/229816762_Electrical_conductivity_in_heterogeneous_polymer_systems._V_(1)_Further_experimental_evidence_for_a_phase_transition_at_the_critical_volume_concentration?ev=prf_pub
https://www.researchgate.net/publication/233979584_Dispersion_hypothesis_and_non-equilibrium_thermodynamics_key_elements_for_a_material_science_of_conductive_polymers._A_key_to_understanding_polymer_blends_or_other_multiphase_polymer_systems?ev=prf_pub
I would assume that you could incorporate a few percent, max 10% before the system will get hazy. I would assume that you want to keep the concentration below the so-called "critical volume concentration" (you need to read the articles to understand what is happening in such systems).
Good luck, let me know what you found out!
Article Electrical conductivity in heterogeneous polymer systems. V ...
Article Dispersion hypothesis and non-equilibrium thermodynamics: ke...
the reason for that the system would loose transparency is the flokkulation of the dispersed particles which I describe in these (and many more) articles.
I think small size is better for low scattering and dispersion of particles in the polymer is very important along with refractive index matching. To make particles dispersible in the matrix I am using organic coating on the the surface but as I say my goal is to load higher concentration, even surface coating is not helpful. I am using rare earth fluoride s and oleic acid as surface coating organic material.
if the dispersed particles are around 100 nm, the refractive index does not play any role, only absorption (hence if absorption in visible range, the particles will xreate some colour, but still transparent; if absorption only in UV or IR, then colourless-transparent).
The question here is how much one can load / disperse before transparency is lost, for that I have commented above.
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