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Cambridge Shear Cell

The Cambridge Shear Cell (CSS) was a product of the 1980s. One of my first PhD students, Diane Graziano, was given the task of developing with me an optical shearing rig that could be used to study the then recently discovered Polymer Liquid Crystals. A Cambridge Technician within the Department of Chemical Engineering, Alan Butcher, helped us design and build two prototypes before a successful unit was achieved and one of the Polymer Fluids Group Post Doctorals, Tim Nicholson provided software. The first paper on optical images from the CSS were published in
D.J.Graziano and M.R. Mackley.
Disclinations observed during the shear of MBBA.
Mol. Cryst. and Liquid Cryst. 106(1/2), 73 (1984).

Subsequently, Arnold Kamp, who was the director of a company Linkam Scientific, offered to commercialise the instrument and Linkam took over the design. Since the mid 1980s until now, several hundred CSS’s have been manufactured by Linkam and the design itself has steadily evolved and been improved. To link with Linkam; go to  www.linkam.co.uk/css450-features/

Below is a movie clip example of how applied shear using the CSS can reveal in this case, unexpected behaviour for an initial dispersion of carbon nanotube aggregates. This astonishing video was taken by Anson Ma. You need to be patient and watch the development of a “helical banding” microstructure develop from  initially random clusters of CNT aggregates. The thickness of the field of view is about 50 microns and shear is applied by the relative movement of the bottom plate with respect to a fixed top plate.

Carbon Nanotube (CNT) aggregate Helical banding. Anson Ma 2005.

Papers relevant to the Cambridge Shear System (CSS)

Copyright © Malcolm Mackley.