Heat Capacity of Nanoparticles - Experimental Determination

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Discussion Overview

The discussion revolves around the experimental determination of heat capacity in nanoparticles, exploring the challenges and methodologies involved in measuring this property. It includes considerations of laser heating, temperature measurement techniques, and the significance of accurate heat capacity data in various applications.

Discussion Character

  • Exploratory
  • Technical explanation
  • Debate/contested

Main Points Raised

  • One participant questions the effectiveness of laser heating for determining heat capacity and the methods for measuring nanoparticle temperature, suggesting potential difficulties in these areas.
  • Another participant challenges the assumption that measuring heat capacity in nanoparticles is inherently more difficult than for other materials.
  • A participant lists several reasons for potential difficulties, including the small size of nanoparticles complicating insulation and aggregation, the importance of heat capacity data in applications like hydrogen storage, and the challenges of accurately measuring temperature during heating.
  • It is noted that heat capacities are typically measured calorimetrically, with a suggestion that single atom/molecule heat capacities can be determined spectroscopically, though this may not be suitable for nanoparticles.

Areas of Agreement / Disagreement

Participants express differing views on the challenges associated with measuring heat capacity in nanoparticles, with no consensus reached on whether these challenges are greater than those for other materials.

Contextual Notes

Limitations in the discussion include assumptions about measurement techniques, the dependence on specific experimental setups, and unresolved questions regarding the interaction of nanoparticles with their environment during measurement.

Who May Find This Useful

Researchers and practitioners in materials science, nanotechnology, and thermal analysis may find this discussion relevant, particularly those interested in the thermal properties of nanoparticles and their applications.

acb
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I know little about the experimental measurements of heat capacity. I can see you'd need to know both how much energy you've transferred to a nanoparticle, and measure the temperature change resulting to ascertain it. This brings me to my questions:

How effective is laser heating of nanoparticles for determining heat capacity?
How is temperature of the nanoparticle measured? An infrared thermometer like device?

I'm guessing the answers are "Not very", and "No", because otherwise many mysteries in materials science would have already been solved. To reframe my question:

Would someone like to tell me about the difficulties of measuring heat capacities in nanoparticles?
 
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What makes you think there's any more difficulty to measurement of heat capacity of nanoparticles than there is of any other material?
 
A few reasons:

1) It's very small, and so insulating it might be difficult while also keeping it from aggregating with something else.
2) This is a very important topic. I know that in hydrogen storage, for example, people would very much like to know the heat capacity of nanoparticles they attempt to hydride, as that would allow them to separate the components of a (hydrogen) desorption reaction free energy. That is, if say: metal-hydride -> hydrogen + metal, then you're very interested in what the heat capacity of the metal is vs. the metal-hydride, as that will dominate the thermodynamics. Medical applications seem abundant for nanoparticles also. Basically this point summarised is: "If it's so important, where are the numbers?"
3) Back to (1) - how do you measure the temperature of a nanoparticle? Measuring its emitted radiation might work, but then how do you heat it (a laser would surely mess with that reading)? Then if you try heating it an insulator, via convection (like in an oven), how do you keep it from reacting with its container? It seems like there would be temperatures beyond which the entire exercise was fraught with difficulty.

I really don't know though. Is it harder?
 
Heat capacities are commonly measured calorimetrically, X moles (or mass) of material are raised from an initial T to a final T and necessary heat measured, or measured heat is applied and temperature difference is measured. Single atom/molecule heat capacities can be determined spectroscopically, but I don't think I'd try it for nanoparticles.
 

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