Prof Karl S Ryder
Professor of Physical Chemistry
B.Sc., D.Phil., (Sussex).
Tel: +44 (0)116 252 2088
Research Group: Materials & Interfaces
My research activities cover three main project areas detailed below. Underpinning all these areas is an interest in electrochemistry, electrochemical interfaces and materials. The research carried out at the University of Leicester, in collaboration with both Professor Abbott and Professor Hillman, is aimed at novel and interesting electrochemical processes and materials, and draws upon many state of the art techniques for surface and interfacial characterisation. These include probe microscopy, x-ray photoelectron spectroscopy (NCESS) neutron reflectivity (ILL, ISIS) electrochemical acoustic impedance spectroscopy and others.
The Leicester group is at the centre of a large European network exploring the properties of novel ionic liquids as replacement technologies for the metal finishing industry. These processes include metal plating, e.g. Zn, Ni, Cr and also electrochemical dissolution processes such as polishing. The IONMET consortium consists of 33 partners both industrial manufacturers and academic researchers. Our role at Leicester is to investigate the underlying science, physical chemistry and electrochemical properties of the new processes.The images above and below are taken from a study of electrochemical polishing of stainless steels. They show a sample with both rough (native, unpolished) regions and the smoother electropolished regions. The liquid used for this process is a very benign, non-toxic liquid that now provides an alternative to the traditional mixture of strong toxic inorganic acids. These studies are also carried in conjunction with Scionix a University of Leicester spin-out company.
We are currently using atomic force microscopy (AFM) to study a variety of electrochemical interfaces e.g thin polymer films and metal electrode interfaces both in dry air and in liquid. The latter provides a severe technological challenge but the Department has a new DI Nanoscope III instrument (pictured below) which represents the state of the art in probe microscopy. This instrument also forms part of the University wide Advanced Microscopy Centre.
Recently we have applied the AFM to the study of thin film electroactive polymer interfaces. These have many uses in the emerging technology of plastic electronic devices. The image below is taken of a polymer layer deposited on a thin film of gold supported but a quartz substrate. The three layers of the sample can be clearly seen in the 3D projection (left) and their relative thickness can be quantified using profilometry.
Electronic and electroluminescent conducting polymers
In collaboration with Professor Mortimer at Loughborough University we are studying the properties of electronically conducting polymer materials that change colour as a function of applied potential. These electrochromic materials have applications in display devices, smart mirrors and windows in controlled environments.The diagram below shows a surface that defines the light absorption of a thin film of polymer as a function of time, where time is also related to potential. At the starting time (t = 0) and the end time (t = 600 s) the polymer absorbs strongly in the red (ca 600 nm) so the material appears blue. In the middle of the surface, however, the polymer is only weakly absorbing and so appears almost colourless!
Surface showing optical properties of a thin film of conducting polymer. Electrochemical absorbance plot: absorbogram. The slope of this surface (in the absorbance time plane) tracks with potential in a manner that is similar to the current (dQ/dt) indicating that charge injection and colour intensity are related.
- “Electroplating using Ionic Liquids”, Andrew P. Abbott, Gero Frisch and Karl S. Ryder, Annual Review of Materials Research, 2013, 43, 1.
- ."Ion transfer mechanisms accompanying p-doping of poly(3,4-ethylenedioxythiophene) films in deep eutectic solvents" A. Robert Hillman, Karl S. Ryder, Christopher J. Zaleski, Claire Fullarton and Emma L. Smith, Z. Phys. Chem., 2012, 26, 1049.
- “Advanced Surface Protection for Improved Reliability PCB Systems (ASPIS)”, Andy Ballantyne, Greg Forrest, Martin Goosey, Asta Griguceviciene, Jurga Juodkazyte, Rod Kellner, Aleksandr Kosenko, Rimantas Ramanauskas, Karl Ryder, Algirdas Selskis, Rima Tarozaite and Erik Veninga, Circuit World, 2012, 38(1), 21.
- "Electrolytic Processing of Super-alloy Aerospace Castings using Choline chloride-based Ionic Liquids", A.P. Abbott, N. Dsouza, P. Withey and K.S. Ryder, Trans. IMF, 2012, 90(1), 9.
- “Mechanism for Formation of Surface Scale During Directional Solidification of N-Based Superalloys”, H. Dong, N. D'Souza, G. Brewster and K.S. Ryder, Metallurgical & Materials Trans A, 2012, 43, 1288.
- "The Electrodeposition of Silver Composites using Deep Eutectic Solvents", Andrew P. Abbott, Khalid El Ttaib, Gero Frisch, Karl S. Ryder and David Weston, Phys. Chem. Chem. Phys., 2012, 14, 2443.
- “Ionometallurgy: Designer Redox Properties for Metal Processing”, A.P. Abbott, G. Frisch, S.J. Gurman, A.R. Hillman, J. Hartley, F. Holyoak and K.S. Ryder, Chem. Commun., 2011, 47, 10031.
- “The Effect of Additives on Zinc Electrodeposition from Deep Eutectic Solvents”, Andrew P. Abbott, John C. Barron, Gero Frisch, Karl S. Ryder and A. Fernando Silva, Electrochimica Acta, 2011, 56, 5272.
- “Double Layer Effects on Metal Nucleation in Deep Eutectic Solvents”, Andrew P. Abbott, John C. Barron, Gero Frisch, Stephen Gurman, Karl S. Ryder and A. Fernando Silva, Phys. Chem. Chem. Phys., 2011, 13, 10224.
- “Do all ionic liquids need organic cations? Characterisation of [AlCl 2.nAmide]+ AlCl4- and comparison with imidazolium based systems”, Andrew P. Abbott, Hadi M. A. Abood, Andrew D. Ballentyne and Karl S. Ryder, Chem. Commun, 2011, 47, 3523.