Posts from October 2016

The Institut Charles Sadron at the CNRS-University of Strasbourg uses the Quorum Cryo-SEM preparation system for research in polymers and self-assembled systems

The Quorum PP3010T's ability to provide stable temperature regulation of samples ensures the facility gets the highest resolution when imaging delicate materials.

The Institute Charles Sadron is a CNRS-Institute located at the University of Strasbourg and performs fundamental and applied research on polymers and self-assembled systems. Dr Marc Schmutz works in the Electron Microscopy facility where he uses a Hitachi SU8010 Ultra High Resolution Field Emission Scanning Electron Microscope in conjunction with a PP3010T Cryo-SEM preparation system from Quorum Technologies. It is used to study a broad variety of materials from crystalline polymers to dragonfly wings. It is vital to be able to observe samples in, as close as possible to, their native state, either hydrated or in organic solvents.

Describing his choice of cryo-preparation system, Dr Schmutz says, “We picked the Quorum system because of its stable temperature regulation; each part of the system is independently controlled (cold stages and cryo-shields). This makes sure we will get the highest resolution when imaging our delicate materials.”

Examples of this work are shown in a recently published paper in the ACS Journal of Physical Chemistry where the drying mechanisms in plasticised latex films are studied with respect to their horizontal drying fronts. The drying kinetics of latexes with particles made progressively softer by adding increasing amounts of a plasticiser, in relation to speeds of horizontal drying fronts and particle deformation mechanisms are reported. [1] To examine the extent of particle deformation inside the dry films, a special sample holder was designed and built, allowing us to take cryo-SEM images of a cross section. Samples of the film were cut out with a razor blade, then fixed in the holder and rapidly plunged into liquid nitrogen slush (in the Quorum PP3010T PrepDek). After introduction into the preparation chamber, the films were then freeze-fractured at −150 °C with a cooled scalpel blade under high vacuum and coated with a thin layer of platinum. They were subsequently imaged in the SEM. 

The PP3010T is a highly automated, easy-to-use, column-mounted, gas-cooled Cryo-SEM preparation system suitable for most makes and models of SEM, FE-SEM and FIB/SEM. 



Left: Quorum PP3010T Cryo preparation system (left) mounted on Hitachi SU8010 FE-SEM at ICS-CNRS-unistra.

(Above: Latex film at high water content vitrified with the Quorum PT3010T. Small arrows point to the latex beads and the longer ones to the water area. (unpublished work))




Reference

1   Drying Mechanisms in Plasticized Latex Films: Role of Horizontal Drying Fronts, V. Divry, A. Gromer, M. Nassar, C. Lambour, D. Collin, and Y. Holl, J. Phys. Chem. B, 2016, 120 (27), pp 6791–6802. DOI: 10.1021/acs.jpcb.6b03009