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Excellence in Broadband Dielectric Spectroscopy • Impedance Spectroscopy • Conductivity Spectroscopy

Materials Studies Under Pressure

It is well known that complete characterization of molecular dynamics in materials must include temperature (T) and pressure (P) experiments. Particularly in polymer science and research the effect of pressure on relaxation spectra is hardly explored.

Pressure tunability creates a whole new research landscape and opens a new pathway to nano structured materials.

For industrial applications pressure can be used as an unique way to control crystallization processes such as nanocrystal growth.

High pressure system overview

The NOVOCONTROL high pressure dielectric analyzer allows scientists to study the effect of temperature and pressure on materials simultaneously. 

The sample is placed between two parallel electrodes of 30 mm diameter. The electrodes are connected by flexible leads to high-pressure feed-through connectors.   Further connection to the Alpha analyzer is performed by standard BNC cables. The electrodes are inserted into a high pressure test cell that can be pressurized by an inert fluid such as silicon oil.

The integrated hydraulic pump features a maximum pressure of 3000 bar. The temperature of the test cell is controlled by electric heating elements over a range from ambient to 250 °C.

Features

  • Turnkey high-pressure system including pneumatic hydraulic pump, sample cell, pump for closing pressure, electronic pressure sensor, broadband dielectric spectrometer, software WinDETA, data acquisition unit
  • Pressure range 0 .. 300 MPa (0 .. 3 kbar)
  • Temperature control of sample cell between 25 °C and 250 °C for software controlled multi dimensional measurements including temperature
  • Alpha dielectric / impedance analyzer included. Frequency range 10-5 Hz to 107 Hz, impedance range 0.01 to 1014 Ω, accuracy in loss factor tan(δ)<3⋅10-5.
    In combination with the pressure cell, the following limits apply due to cell isolation and oil conductance:
    impedance <109 Ω,  frequency < 1 MHz, tan(δ) accuracy may be decreased
  • High pressure sample cell for dielectric and conductivity material measurements under pressure and temperature
    Pressure cell dimensions: 50 mm height, 34 mm diameter

Important publications

  1. Andrei Diaconu, Simona-Lacramioara Lupu, Ionela Rusu, Ioan-Marian Risca, Lionel Salmon, Gabor Molna, Azzedine Bousseksou, Philippe Demont, and Aurelian Rotaru. 2017. Piezoresistive Effect in the [Fe(Htrz)2(trz)](BF4) Spin Crossover Complex. J. Phys. Chem. Lett. 2017, 8, 3147−3151. DOI: 10.1021/acs.jpclett.7b01111
  2. G. Floudas and T. Reisinger. Pressure dependence of the local and global dynamics of polyisoprene. J. Chem. Phys., Vol. 111, No. 11, 15 September 1999. DOI: 10.1063/1.479774
  3. G. Floudas and C. Gravalides and T. Reisinger and G. Wegner. Effect of pressure on the segmental and chain dynamics of polyisoprene. Molecular weight dependence. The Journal of Chemical Physics 111, 9847 (1999) DOI: 10.1063/1.480327
  4. G. Floudas. Effects of pressure on systems with intrinsic orientational order. Prog. Polym. Sci. 29 (2004) 1143–1171. doi:10.1016/j.progpolymsci.2004.08.004