Dr Avtar Matharu

01904 324187
Email: avtar.matharu@york.ac.uk

Functional Materials – Liquid Crystals to Optical Data Storage

Research in the group focuses on the synthesis and characterisation of novel functional organic materials for use in state-of-the-art 21^st Century applications. We have for many years studied liquid crystals, materials that exhibit a unique fourth state of matter which exist between the crystal and liquid states of matter. Liquid crystals impact our daily lives and are found almost everywhere, for example from the soap we use for personal hygiene to the mobile phone or laptop commuter that we use to communicate with each other. Liquid crystals are essentially low molar mass organic compounds comprising aromatic and heteroaromatic moieties appended to alkoxy and alkyl chains. The design, synthesis and distribution of these groups in the liquid crystal are crucial to the final characteristics of the compound. We liaise with global electronics companies to design state of the art materials for 21^st century applications. Our latest research brings us together with the DTI and several UK Companies to explore ways of recycling liquid crystal waste material from the ever increasing number of defunct LCD devices that are now being disposed. Below is a selection of our current projects:

Liquid Crystals (LCs) at Various Wavelengths of Light (Goodby, Bruce, Vladimirov, Matharu, Saez and Bates, 2006-2011, EPSRC Funded, £399, 658, Award Number, EP/D055261/1)

Funding has been accrued as part of an EPRSC Platform Grant to sustain and develop new research areas in liquid crystal science under the remit of liquid crystals at various wavelengths of light.

Novel Media For Terabyte Holographic Data Storage (2005-6, EPSRC Funded, £63138, Award Number, EP/C542223/1)

The amount of information produced annually is exponential in growth. Currently available magneto-optical materials have reached their storage buffer due to physical limitations imposed by the super-paramagnetic effect and will not be able meet future storage requirements. The simple fact is that present optical storage technology suffers from an absence of functional organic materials that apply to the next generation of commercially available laser diodes (Nichia blue lasers, 400 - 500 nm). Although 'Blu-Ray' DVD technology has arrived with storage capacities ranging from 27-54 GB (operating at 405 nm with 0.85NA), the materials are still to be optimised. Higher storage densities of up to 80 GB may be achieved by depositing several layers of a material which is not ideal due to loss of resolution. An ideal material is yet to be realised. In addition, the future will demand a shift to even shorter wavelengths such as UV so that even high capacities may be managed.

Funding has been accrued to investigate organic-based polyesters comprising both side-chain mesogenic and side-chain heterocyclic photoresponsive groups as novel media for terabyte holographic data storage.

REFLATED: Recovery of Flat LCDs using Advance Technological Processes (2006 -2009, DTI Funded, £364, 087, Award Number, TP/4/ZEE/6/I/21061)

The success of LCDs in modern day society may be perversely judged by the ever increasing number of LCD devices discarded on a daily basis. To combat the stockpiling of defunct electronic materials, Directive 2002/96 (WEE directive) states that producers of electrical and electronic equipment must introduce systems for taking back waste electrical and electronic equipment that are free for private end users. LCDs containing WEE has been identified as one of the fastest growing sources of waste in the EU, increasing by 16-28% every five years (and predictions are expected to be conservative). These systems must be in place by August 2005. Targets for recovery (80%) and recycling (75%) are set for December 2005. At present there are no commercially viable, environmentally friendly solutions either for recovery and/or purification of LCD waste. We have been commissioned by the DTI to provide solutions to safe and effective recovery of liquid crystal material from defunct LCD devices. The project spans three years, involves several companies with a total budget of £1.7 M.

Selected Publications

Liquid Crystal Displays: from devices to recycling.
A S Matharu, P B Karadakov, S J Cowling, G Hegde and L Komitov, 2011, Liquid Crystals, 38, 207-232.
Photoalignment Properties of 2- and 3-Thienylacrylates Bearing Laterally Fluorinated Azobenzene Moieties.
G Hegde, D Chambers-Asman, A S Matharu and L Komitov, IDW’10, 2010, 73-76.
From LCDs to materials for medical application.
A J Hunt, A S Matharu and J H Clark, Education in Chemistry – RSC, 2010, 47, 176-179.
Expanding the potential for waste polyvinyl-alcohol.
A J Hunt, V L Budarin, S W Breeden, A S Matharu and J H Clark, Green Chem., 2009, 11, 1332-1336.
Extraction of liquid crystals from flat panel display devices using both liquid and supercritical carbon dioxide.
A J Hunt, J Clark, S W Breeden, A S Matharu, C Ellis, J W Goodby, J A Bottomley and S J Cowling, 11th International Supercritical Conference Proceedings, May 2008.
A S Matharu and Y Wu, in "Electronic Waste Management, Issues in Environmental Science and Technology", 2008, 26, ed. R E Hester and R M Harrison, RSC Publishing, Cambridge UK.
Holographic recording in thiophene-based polyester.
A S Matharu, D Chambers-Asman, S Jeeva, S Hvilsted and P S Ramanujam, Journal of Materials Chemistry, 2008, 18, 3011-3016.
An efficient direct method for azo-coupling of methoxythiophenes.
A Matharu, P Huddleston, S Jeeva, M Wood and D Chambers-Asman., Dyes and Pigments, 2008, 78, 89-92.
Structure-Property investigation of 2- and 3-thienylacrylates bearing laterally fluorinated azobenzene moieties.
A S Matharu and D Chambers-Asman, Liquid Crystals, 2007, 34, 1317-1336.
Synthesis and optical storage properties of a thiophene-based holographic recording medium.
A S Matharu, S Jeeva, P R Huddleston and P S Ramanujam, J Mater Chem, 2007, 17, 4477-4482..
Liquid crystals for holographic optical data storage.
A S Matharu, S Jeeva and P S Ramanujam, Chem. Soc. Rev., 2007, 36, 1868-1880.
Laterally fluorinated liquid crystals containing the 2,2' - bithiophene moiety.
A S Matharu, S Cowling and G Wright, Liquid Crystals, 2007, 34, 489-506.
Electrically commanded surfaces for nematic liquid crystal displays.
L Komitov, B Helgee, J Felix and AS Matharu, Appl. Phys. Lett., 2005, 86, 023502
Photoinduced anisotropy in a family of amorphous azobenzene polyesters for optical storage.
L. Nedelchev, A.S. Matharu, S. Hvilsted and P.S. Ramanujam, Applied Optics, 2003, 42(29), 5918-5927.
Polarisation holographic and surface-relief gratings at 257 nm in an amorphous polyester.
P S Ramanujam, L Nedelchev and A S Matharu, Optics Letters, 2003, 28(13), 1072-1074.
Photochromic Processes for High Density Optical Storage.
P S Ramanujam, R H Berg, S Hvilsted, A Matharu, L Nedelchev and E Loroncz, Optical Data Storage Technical Digest, 2003, 66-69.
Photoinduced macroscopic chiral structures in a series of azobenzene copolyesters.
L Nedelchev, L Nikolova, A Matharu, and P S Ramanujam, Appl. Phys. B: Lasers and Optics, 2002, 75(6-7), 671-676.

Department of Chemistry