Insplorion’s NPS technology measures changes in optical properties (refractive index) in the first few tens of nanometers from a sensor surface. Within the broad area of Material Science it has proven especially effective in research on diffusion in porous films, Tg of thin polymer films and hydrogen sensing/storage. Here the Insplorion technology overcomes numerous experimental challenges.
Monitoring the hidden interface between a porous film and substrate
Diffusion of small molecules into and out of a porous material on a small scale is an experimental challenge even for a very well-equipped lab. For drug delivery and other slow release as well as applications where a maximum of material is desired inside the porous matrix is desired, NPS can prove an invaluable tool.
NPS has been used to follow the following processes:
Time dependence of dye impregnation of mesoporous TiO2 for optimization of Dye Sensitised Solar Cells.
Quantification of the diffusion coefficient of the dye in the mesoporous material.
Tg of ultra-thin polymer films and nanostructures/particles
In ultra-thin polymer films the glass transition temperature Tg is known to become size/thickness dependent due to the existence of a near surface layer (a few nm thick), where polymer segments have a different mobility. Insplorion’s NPS technology provides the researcher in the field of thin polymer films with a powerful research tool to study phase transitions.
NPS has been successfully used to, among others, address the following phenomena:
The thickness dependence of the glass transition temperature (Tg) thin films of atactic poly (methyl methacrylate) (PMMA).
The size dependence of the glass transition temperature (Tg) in polystyrene (PS) nanoparticles.
Insplorion’s NPS technology provides the researcher in the field of hydrogen storage and solid-state reactions with a new and powerful research tool to overcome numerous experimental challenges. NPS measurements is focused on a well-defined model system with a small amount of sample in a well-controlled microenvironment at “in operando” conditions. This leads to minimized gradients of all kinds, as well as distortions from broad particle size distribution. The high time resolution enables fast processes to be monitored typical in solid state reactions at high temperatures.
INPS has been successfully used to, amongst others, address the following issues in the area of hydrogen storage in nanosized storage entities:
- The size dependence of the hydriding and dehydriding kinetics in Pd nanoparticles for particles in the D < 5 nm size range.
- The size dependence of hydride formation and decomposition thermodynamics in Pd nanoparticles in the D < 5 nm size range.
- A study of the size dependent hysteresis between hydride formation and decomposition in metallic nanoparticles.
- Quantitative single particle investigations of hydride formation thermodynamics in Mg and Pd nanoparticles.