Thin film calixresorcinarene membranes for chemical sensing. WILKOP, Thomas. Available from the Sheffield Hallam University Research Archive (SHURA) at: http://shura.shu.ac.uk/20538/ A Sheffield Hallam University thesis This thesis is protected by copyright which belongs to the author. The content must not be changed in any way or sold commercially in any format or medium without the formal permission of the author. When referring to this work, full bibliographic details including the author, title, awarding institution and date of the thesis must be given. Please visit http://shura.shu.ac.uk/20538/ and http://shura.shu.ac.uk/information.html for further details about copyright and re-use permissions. Fines are charged at 50p per hour 2 B a p r 9nn«; U- • l s> 2h Aiir, ProQuest Number: 10701185 All rights reserved INFORMATION TO ALL USERS The quality of this reproduction is dependent upon the quality of the copy submitted. In the unlikely event that the author did not send a com plete manuscript and there are missing pages, these will be noted. Also, if material had to be removed, a note will indicate the deletion. uest ProQuest 10701185 Published by ProQuest LLC(2017). Copyright of the Dissertation is held by the Author. All rights reserved. This work is protected against unauthorized copying under Title 17, United States C ode Microform Edition © ProQuest LLC. ProQuest LLC. 789 East Eisenhower Parkway P.O. Box 1346 Ann Arbor, Ml 48106- 1346 Thin Film Calixresorcinarene Membranes For Chemical Sensing Thomas Wilkop A Thesis submitted in partial fulfilment of the requirements of Sheffield Hallam University for the degree of Doctor of Philosopy April 2001 School of Engineering 4^££tts centb^ Copyright © 2001 by Thomas Wilkop The copyright of this thesis rests with the author. No quotation from it should be published without his prior written consent and information derived from it should be acknowledged. Declaration I hearby declare that the work carried out in this thesis has not been previously submitted for any degree and is not currently being submitted in candidature for other degree. Signed .......................................................... Candidate The work in this thesis was carried out by the candidate. Signed Signed Directors of Studies Signed .......................................... Candidate Don’t panic Cover Title of the fictitious “Hitchhikers Guide To The Galaxy” by Douglas Adams Acknowledgements My research work was conducted in the framework of a joint project between Sheffield Hallam University and the University of Sheffield. This gave me the opportunity to experience the best of two worlds, making it a very educational experience. My thanks go to Sheffield Hallam University which provided the financial support to carry out this study. I would like to thank my supervisors Professor Asim Ray and Professor Rob Yates for their open mindedness, that gave me the freedom to follow up new developments in the process of the research and for providing the means to carry them out. Countless hours in and around the cleanroom were excellently supported by the principal technician Geoff France. The spelling and grammar in my thesis was markedly improved, upon the suggestions and corrections of Brian McQuillin, whom I thank for doing this most boring proof reading. I have “learned the ropes” for most of the analytical tools and the instrumentation used from Dr. Aseel Hassan, who never tired to assist fixing the odd problem that occurred. My special thanks goes to Dr. Aleksey Nabok with whom I had countless fruitful discussions, who always made time for this vital brainstorming sessions during which I learned more than from many books. The chemical side of my work was excellently supported by discussions and active support by Dr. Steffi Krause who further provided the facilities for some of the experiments carried out. It was the chemical part of my work that gave me the greatest understanding of my work in the field of chemical sensors and also provided the most educational part. Abstract Novel applications for calix[4]recorcinarene (C[4]RA) sensing membranes have been investigated. A comprehensive deposition study was carried out, encompassing casting, spin coating and Langmuir Blodgett (LB) deposition. The spin coating thickness d depended on the angular velocity co, following the description of d = C'C0 X with coefficients of x - 0.44 and - 0.48 for concentrations of 1 mg/ml and 2mg/ml respectively. The analysis of the LB deposited films established a thickness of 0.95 nm for a monolayer. Furthermore the C[4]RA, was successfully employed as a deposition matrix for a non surface active polymer, poly-ortho-methoxy aniline (POMA), which can otherwise not be deposited by LB. The composite film showed good homogeneity and based on thickness and UV measurements a structural model for it was developed, in which two polymer strands aligned themselves per C[4]RA layer, resulting in a monolayer thickness of 2 .1 - 2 . 2 nm. The response of the C[4]RA and the composite membranes to a variety of organic and inorganic gaseous pollutants was investigated by Surface Plasmon Resonance studies, conductivity and capacitance measurements and UV spectroscopic studies. The integration of cast films into the gate of a charge flow transistor, is the first application of pure calixarenes in a conduction based sensor. The turn on response of the transistor is modulated by a variety of organic vapours, at the saturation vapour pressure, showing selectivity between polar and non-polar solvents, i.e. chloroform, methanol, acetone and hexane, with no cross sensitivity to water vapour. The modulation lies within factors of 45 for CHCI 3 and 13 for CH 3OH. The conductivity increase is partially attributed to micro-condensation of the vapours inside the micro- porous membrane. A successful application of this implementation as an explosion guard sensor for acetone is demonstrated. Gold electrodes with and without C[4]RA LB films have been characterised using impedance spectroscopy and cyclic voltammography. The modification of the gold electrodes by the C[4]RA film changes their constant phase element impedance, given by -— '~Qy 5 60 being the angular velocity. The observed values were from Q = 0.725*1 O ' 5 Farad and n = 0.87 to Q = 0.828*1 O ' 6 Farad and n = 0.82. Organic analytes like, chloroform and acetone in water can be successfully detected with these electrodes. It is shown by cyclic voltammetry, that the permeability of the C[4]RA LB films is modulated by the organic solvents. Table of Contents Abstract_____________________________________ I Table of Contents II Chapter one 1 Introduction ____________________________ 1 1.1 The structure of this thesis_____________ 3 1.2 Bibliography_____________________________________________________ 5 Chapter two 2 Chemical Sensors_______________________ 6 2.1 The human nose__________________________________________________ 6 2.2 Electronic noses___________________________________________________ 8 2.3 Multivariate analysis____________ 10 2.4 The human tongue_______________________________________________ 11 2.5 Electronic T ongues_______________________________ 12 2.5 Animal chemo-senses____________________________________________ 13 2.6 Definition of a chemical sensor____________________________________ 14 2.7 Thermodynamics of sensor analyte interaction _______________________ 15 2.8 Intermolecular forces between the analyte and the sensing membrane 17 2.9 References______________________________________________________ 17 II Chapter three 3 Calixarenes and Resorcinarenes_______________ 22 3.1 Synthesis of Resorcinarenes________________________________________ 23 3.2 Conformations ___________________________________________________ 24 3.3 Derivatives of Calixarenes and Resorcinarenes________________________ 25 3.4 Calixarenes and Resorcinarenes as Host Molecules____________________ 26 3.5 Calixarenes and Resorcinarenes in Sensing Membranes_______________ 29 3.5.1 Sensors for Metal Ions_________________________________________ 30 3.5.2 Sensors for Organic Analytes___________________________________ 31 3.5.2.1 In aqueous media___________________________________________ 31 3.5.2.2 In a ir____________________________________ 32 3.6 Non-chemical Sensor Orientated Applications for Calixarenes and Resorcinarenes_______________________________________________________ 33 3.7 References _______________________________________________________ 35 Chapter four 4 Materials andfilm deposition__________________ 39 4.1 Calix[4]resorcinareneC7Hi5 and Poly-ortho-methoxy aniline ___________ 39 4.1.1 Electroactive conjugated polymers and deposition thereof__________ 40 4.2 Thin film deposition principles_____________ 42 4.2.1 Casting______________________________________________________ 42 4.2.2 Spin coating__________________________________________________ 43 4.2.2.1 Factors influencing the film properties of spun films_____________ 45 4.2.3 • Langmuir-Blodgett (LB) film deposition__________________________ 47 4.2.3.1 Factors influencing the film deposition________________________ 48 4.3 Deposition details and experimental results___________________________ 50 4.3.1 LB films____________________________ 50 4.3.1.1 Deposition details for C[4]RA film s___________________________ 50 II 4.3.1.2 Film thickness analysis of pure C[4]RA multilayer structures 52 4.3.1.3 Deposition details for C[4]RA/POMA composite films___________ 52 4.3.1.4 Thin film analysis of the composite membranes_________________ 55 4.3.1.4.1