Theory
PSS PoroCheck uses recognition of porous structures by diffusion of test molecules of different size into the pores under normal operating conditions of the porous material (and not in vacuum). This means that PoroCheck can also measure fragile samples and investigate materials in different states (dry, swollen, partially adsorbed).
Chromatographic porosimetry has proven to be a very useful method to produce realistic results with many additional benefits. It relies on the permeation of test molecules into the porous material and relating sample retention to pore size using chromatographic separation theory developed by Cassasa and Gorbunov. The best and most widely available instrument for running the analysis is a conventional LC instrument, which is present in most labs. Running a LC instrument is straight-forward to most users and needs no additional training as would be the case with a gas adsorption or Hg intrusion device. Using existing equipment for pore size analysis also needs no additional investment into instrumentation for a new method.
All results are retrieved from a table relating molecular size to chromatographic retention. The pore size distribution is calculated based on a flexible chain model assuming fixed pore boundaries. Cylinder and slit models are available to describe the pore structure.
Detailed analysis of pore accessibility yields to a multitude of analytical results, which can be derived from the pore size distribution. Results can be presented in many ways (differential or cumulative representation, volume or surface distribution).
PoroCheck is the first and only software which calculates error margins for 50
and 95% accuracy.
Further reading:
Theoretical background:
- A.A. Gorbunov, L. Y. Solovyova, and V.A. Pasechnik, J.Chromatogr., 448, 307 (1988)
- A.A. Gorbunov, A.M. Skvortsov, Polymer, 32, 3001 (1991)
- E.F. Casassa, J. Polym. Sci., Part B, 5, 773 (1967)
- E.F.Casassa, Macromolecules, 9, 182 (1976)
Implementation and application:
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