Dear Dr. Nair:

See, from room temperature up to high temperature the thermal conductivity is a complex phenomenon.

Two major mechanism of transport actuate in this property: electrons and phonons.

In fact, another possibilities emerge from another phenomena called of coupling-phenomena.

In this way, thermal conduction mechanism can be modulated from “electron-phonon” coupling (conventional and unconventional), phonon-phonon coupling, … and another, depending on the material and size.

Then, each compound should have a proper thermal-conductivity, from this, since phonon depending on the characteristic of crystalline-lattice for a same cationic specie, the metal form exhibits thermal properties distinct of oxide variety, as an example metallic cooper have a priori distinct thermal properties of copper oxide.

Furthermore, yet due crystalline-lattice features, nanoparticles of cooper oxide should a priori exhibit distinct thermal properties of conventional cooper oxide (with particle having particle size in the range 1 – 10 micrometers). At least, melting point and fusion point should differ. In this sense, metallic nanoparticles should show some kind size or scale effect. Such aspect can be expected since most of atoms of a nanoparticles are in the surface, while a nano-lattice absent of defect is inner.

Best regards

Marcos Nobre

copper and copper oxides are two different things so the thermal conductivity will be totally different. You have to measure the thermal conductivity of copper oxides in one of the thermal conductivity measurment instruments. But once in nano form any material may have  different physical properties.

Dear Dr. Nair:

See, from room temperature up to high temperature the thermal conductivity is a complex phenomenon.

Two major mechanism of transport actuate in this property: electrons and phonons.

In fact, another possibilities emerge from another phenomena called of coupling-phenomena.

In this way, thermal conduction mechanism can be modulated from “electron-phonon” coupling (conventional and unconventional), phonon-phonon coupling, … and another, depending on the material and size.

Then, each compound should have a proper thermal-conductivity, from this, since phonon depending on the characteristic of crystalline-lattice for a same cationic specie, the metal form exhibits thermal properties distinct of oxide variety, as an example metallic cooper have a priori distinct thermal properties of copper oxide.

Furthermore, yet due crystalline-lattice features, nanoparticles of cooper oxide should a priori exhibit distinct thermal properties of conventional cooper oxide (with particle having particle size in the range 1 – 10 micrometers). At least, melting point and fusion point should differ. In this sense, metallic nanoparticles should show some kind size or scale effect. Such aspect can be expected since most of atoms of a nanoparticles are in the surface, while a nano-lattice absent of defect is inner.

Best regards

Marcos Nobre

Thank you Prof. Pushpa for your reply. Do you have any journal paper or some sort of written work which can confirm your claim?..Pls share if you have or if you know any material which explains the thermal conductivity of nanoparticles.

Thank you once again.

Ola Prof. Marcos. Como voce esta?

Thank you for your elaborate answer.So according to your answer the nanoparticles will have different thermal conductivity value as compared to the parent material.I read somewhere that properties change drastically when we come down to nano levels.I would really like to read more about it. Can you suggest me any book or paper available in literature which talks about thermal conductivity of nanoparticles?

Thank You once again Prof. Marcos.

I fully agree with Marcos here. Thermal conductivity is a macro-scale approach that disguises the fundamental processes responsible for the diffusion of heat. Phonons (or latice vibrations) and electrons are the important fundamental energy carriers that needs to be considered when the physical dimensions approaches the length-scales of these phenomena. I suggest checking the book "Microscale and Nanoscale Heat Transfer" by Sobham and Peterson for an in-depth presentation.

Thank you Prof. Erling. I will go through the book recommended by you.

Thank you once again.

Thermal and electrical conductivity of substances depend on the electronic configuration. In pure Cu the electronic arrangement is different CuO or Cu2O where free electrons are trapped by high EN atom oxygen. Therefore both Cu and its oxides have different conductivities. Cu definitely high. 

Dear all,

If a copper thermal conductor is ageing and some oxide layer is formed on the surface, does this oxide layer negatively affect the thermal conductivity? Does anyone know about investigations on this topic?

Thank you for your answers.

Best regards

Ingo Tischer

the thermophysical properties of the nanomaterials are very different as compared with the bulk materials