Fred Davis, BA, DPhil (York)Area Safety Co-ordinator

Tel: +44 (0)118 378-8455

Fax: +44 (0)118 378-6331

Email: f.j.davis@rdg.ac.uk

Polymer Science

There is a continuing need for new or improved materials to meet the ever changing demands of moderntechnology. Polymer systems offer considerable scope for designing materials with new or improvedproperties through the diversity of Organic Chemistry. The Davis Group is concerned with the synthesis ofpolymeric materials with unusual properties, optical, electrical, mechanical etc. In addition, in relation tothe work on Spectral filters we have been concerned with aspects of material degradation and stability, thishas lead to a series of other projects with for example National Grid and ultimately has lead to the designof some novel supercapacitors. (For more information see the Powerpoint presentation on supercapacitorswhich is available for download.) The work has involved extensive collaboration with other Departmentsincluding the Centre for Advance Microscopy, the Centre for Biomimetics, the Department of Horticultureand the Department of Electronics and Computer Science at the University of Southampton. Industrialsponsors

Electrospinning

Electrospinning provides an effective route to the preparation of nano and micro fibres of synthetic andbiological polymers. It is an enabling technology with applications in medical, pharmaceutical, chemical,textile, and electronic industries. The technique produces very fine, nano to micrometer diameter, fibres inrandom mats as shown or in more controlled structures. (More information on the electrospinning project isavailable for download.) Materials are studied with a range of techniques including x-ray scattering,neutron diffraction (see Figure) and a range of microscopy techniques (http://www.reading.ac.uk/cfam/).

Neutron scattering data obtained from a fibre of deuteratedpolystyrene produced by electrospinning. The fibres obtained show adegree of anisotropy.

Liquid Crystalline elastomers

Liquid crystalline elastomers combine the well-known properties of rubber elasticity with the anisotropicproperties of liquid crystals (familiar for their use in display devices). Reading is a world-leader in thesynthesis and study of these materials. Their unique combination of properties has resulted in materialswhich display unusual behaviour. Properties discovered and investigated by the group at Reading include:mechanically-induced molecular alignment, shape changes, shifts in phase transition temperatures, andmemory effects (F.J. Davis, J. Materials Chemistry, 1993, 3, 551-562). Recent developments include anew method of preparing a chiral structure without an excess of specific stereogenic centres, throughimprinting chiral structure on liquid crystalline elastomers (C.D. Hasson, F.J. Davis, and G.R. Mitchell, Mol. Cryst., Liq. Cryst, 1999, 332, 2665, J. Chem. Soc., Chem. Commun, 1998, 2515.

A highmolecular weight styrene isoprene block copolymer (a) in thesolid state (b) as a solution intoluene.

Optical properties of Polymers

We have designed and synthesised a range of polymers which interact with light in a controlled fashion;these include such as non-linear optical polymers and the use of photo-induced shape changes at amolecular level (for example through geometric isomerisation) to manipulate macroscopic polymerproperties, such as refractive index and phase behaviour. Recently we have been involved in the synthesisof photonic band gap materials from block copolymers. As with the cholesteric liquid crystalline polymersthese selectively reflect visible light. One particularly interesting area is the use of polymeric films to controlplant growth as an alternative to chemical sprays (with Professor P. Hadley, Horticulture and Dr A.E.Wheldon, Engineering). Controlling the light incident on plants can influence a range of factors from totalphotosynthetic production, through to the sporolation of Botritys and the generation of secondary products;for example the photo shows the influence of UV blocking materials on the development of phenolicmaterials in lettuce Lollo Rosso lettuce 'Revolution'. The success of this programme can be gauged from thefact that the team were awarded the 1998 Science into Practice award from the Ministry of AgricultureFisheries and Foods and Andersons for their innovative work on SMART greenhouse materials and thetransfer of technology to their industrial partners; in addition a display focusing on these investigations wasawarded a Silver Medal at the 2004 Chelsea Flower Show. The growth control films are marketedcommercially as Solatrol (http://www.bpiagri.com/pdf/solatrol.pdf).

Recent Publications

Polyurethane Based Materials with Applicatons in Medical Devices, F.J. Davis and G.R.Mitchell, in Bio-Materials and Prototyping Applications in Medicine , Eds P. Bartolo and B.Bidanda, Springer, NY, 2008 Pages 27-48.

1.

Chemical, physical and electrical properties of aged Dodecylbenzene 1: Thermal ageing ofmixed isomers in air, I. L. Hosier, A. S. Vaughan, S. J. Sutton and F. J. Davis, IEEE Transactions on Dielectrics and Electrical Insulation 2007, 14 (5): 1113-1124.

2.

The structure of crystallisable copolymers of l-lactide, ε-caprolactone and glycolide, W.Channuan, J. Siripitayananon, R. H.Olloy, M. Sriyai, F.J. Davis and G.R. Mitchell,Polymer, 2005, 46, 6411-6428 .

3.

Chemical and physical properties of aged dodecylbenzene insulating oil, I. L. Hosier, A. S. Vaughan, S. J. Sutton and F.J. Davis, Annual Report Conference on Electrical Insulation andDielectric Phenomena : 225-228, 2005.

4.

Ageing of Insulating Oils: Chemistry and Electrical Properties, I. L. Hosier, A. S. Vaughan, F. J.Davis, P. L. Lewin and S. J. Sutton, Annual Report Conference on Electrical Insulation andDielectric Phenomena : 221-224, 2005.

5.

Development of smart variable stiffness actuators using polymer hydrogels, C. Santulli, S.I. Patel, G. Jeronimidis, F.J. Davis, and G.R. Mitchell, Smart Materials & Structures, 2005, 14(2): 434-440.

6.

Practical Approaches in Chemistry Series: Polymer Chemistry, A Practical Approach Edited byF.J. Davis OUP 2004.

7.

Growth, yield and development of strawberry cv. 'Elsanta' under novel photoselective film cladgreenhouses, J.M. Fletcher, A. Tatsiopoulou, P. Hadley, F.J. Davis, and R.G.C. Henbest, Acta Horticulturae, 2004, 633, 99-106.

8.

Temperature insensitive chiral optical films prepared through the soft imprinting of liquid crystalelastomers, G.R. Mitchell, C.D. Hasson, and F.J. Davis, Abstracts of Papers of the AmericanChemical Society, 2001, 222, 356.

9.

Electric Field Induced Macroscopic Shape Changes in Liquid Crystalline Elastomers, K.H. Ahn, P.M.S. Roberts, F.J. Davis and G.R. Mitchell, Abstracts of Papers of the American ChemicalSociety, 1997, 214, 218.

10.

Liquid Crystalline Elastomers: The Relationship Between Macroscopic Behaviour and the Levelof Backbone Anisotropy, H. Hirschmann, P.M.S. Roberts, F.J. Davis, W. Guo, C.D. Hasson,and G.R. Mitchell, Polymer 2001, 42, 7063-7071.

11.

Phase Transitions in Mixtures of a Nematic Polymer and Chiral Nematic Liquid Crystals whichform Blue Phases, U. Singh, F.J. Davis and H.F. Gleeson, Molecular Crystals and Liquid Crystals, 2001, 357, 239.

12.

Improved Films, F.J. Davis, A. Gilbert, P. Hadley, K. van Haeringen, R. Henbest, S. Pearson,J. West, and A.E. Wheldon, European Patent Application No 00307326.9-2108, 2001

13.

Degradation Of Dodecylbenzene Under Conditions of High Electric Field, R.L. Huynh F.J. Davis, D. Patel, and A.S. Vaughan, Proceedings of 8th International Conference on DielectricMaterials, Measurements and Applications isbn 085296 730 6, 2000.

14.

Phase Behavior and non-periodic crystallisation of Random Aromatic Copolyesters and theirside chain bearing system, Z. He, F.J. Davis R.H. Olley, and G.R. Mitchell, Polymer, 2001, 42, 5351-5363.

15.

Spectral Filters For The Control Of Botrytis Cinerea, J S West, S Pearson, P Hadley, A E Wheldon, F.J Davis , A Gilbert and R G C Henbest, Annals of Applied Biology, 2000, 136, 115-120.

16.