Vibrational spectroscopy studies of interdiffusion in polymer laminates and diffusion of water into polymer membranes. HAJATDOOST, Sohail. Available from the Sheffield Hallam University Research Archive (SHURA) at: http://shura.shu.ac.uk/19741/ 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/19741/ and http://shura.shu.ac.uk/information.html for further details about copyright and re-use permissions. Sheffield Hallam University REFERENCE ONLY ProQuest Number: 10697043 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 10697043 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 Vibrational Spectroscopy Studies of Interdiffusion in Polymer Laminates and Diffusion of Water into Polymer Membranes by Sohail Hajatdoost A thesis submitted in part fulfilment of the requirements of Sheffield Hallam University for the degree of Doctor of Philosophy October 1996 ABSTRACT Confocal Raman microspectroscopy has been used to study the interdiffusion in polymer laminates at the interfacial region between the constituent polymer layers. The effects of the polymer molecular weight, annealing temperature, and annealing time have been studied. Three different laminates with various PMMA molecular weights have been examined, with a view to studying the hydrogen bonding interaction between the alcohol and ester groups of PVOH and PMMA layers. It has been found that v(C=0) band shows no apparent frequency shift due to hydrogen bonding. However, considerable broadening of the v(C=0) band has been observed at the interfacial region. In order to study the effect of annealing temperature, a PAN/PVOH laminate has been chosen. It has been shown that the degree of hydrogen bonding is reduced if the polymer laminate is annealed at a higher temperature than the glass transition temperature of both of the constituent polymers. No significant change has been observed after annealing the laminate for various lengths of time. It has been shown that Raman imaging and Raman microscopy can provide invaluable information about the molecular distribution and chemical interactions of various phases in polymer blends. The diffusion of pure water and also water from some ionic solutions into sulphonated polyetherethersulphone/polyethersulphone, SPEES/PES has been studied using Fourier transform infrared-attenuated total reflectance, FTIR-ATR spectroscopy. The effects of sulphonation level, annealing temperature, ionic concentration, and presence of some ionic species on diffusion of water into SPEES/PES has been examined. In addition the sorption and desorption processes, and diffusion into a laminate of SPEES/PES-PVOH has also been studied. It was found that the above diffusion processes are not Fickian nor Case II and is best described by a dual-mode sorption model. The diffusion coefficient for H20 in various cationic solutions into SPEES/PES has a descending order of Li+ > Cs+ > Na+ > K+. Increasing the ionic concentration results in a decrease in the water diffusion coefficient. It was found that an increase in annealing temperature caused the diffusion curve to become more sigmoidal in shape with a decreases in diffusion coefficient. CONTENTS Chapter 1 1.1. Introduction to infrared spectroscopy 1 1.2. .Molecular vibrations 2 1.3. Anharmonicity 3 1.4. Normal modes of vibration 6 1.5. Fourier Transform Infrared Spectrometry and Interferometry 8 1.5.1. Advantages of FTIR spectroscopy 12 1.6. Attenuated Total Reflectance 14 Chapter 2 2.1. Introduction to Raman spectroscopy 23 2.2. Theory 24 2.3. Sample fluorescence 26 2.4. Raman microscopy 27 2.4.1. Sample heating in Raman microscopy 28 2.4.2. Confocal Raman microscopy 28 2.4.2.1. Theory 30 2.4.3. Raman imaging and mapping 41 2.4.3.1. 3-D Raman mapping 46 2.4.3.2. Application 47 Chapter 3 3.1. Introduction 5 0 3.2. Experimental 52 3.2.1. Polymer laminate preparation 52 3.2.2. Confocal Raman microspectroscopy procedure 54 3.3. Results and discussions 57 3.3.1. Effect of molecular weight 57 3.3.1.1. Interfacial effects 67 3.3.2. Effect of annealing temperature 72 3.3.2.1. Annealing temperature of 65 °C 75 3.3.2.2. Annealing temperature of 75 °C 82 3.3.2.3. Annealing temperature of 90 °C 85 3.3.3. PAA/PAN laminate 87 3.3.4. Effect of annealing time 94 Chapter 4 4.1. Introduction 96 4.2. Experimental 99 4.3. Results and discussion 101 4.3.1. PMMA-PAN blend 101 4.3.2. PAN-PVOH blend 109 4.3.3. Raman confocal mapping of interfacial region in PVOH/PMMA 114 Chapter 5 5.1. Introduction 116 5.2. Polymeric membranes 116 5.3. Water in polymeric membrane 121 5.4. Diffusion of water into polymer 124 5.5. Diffusion behaviour 125 (a) Case I or Fickian (b) Case II (c) Case IH or non-Fickian 5.5.1. Effect of surface concentration on diffusion coefficient 128 5.6. Sorption 129 5.6.1. Dual-sorption model 12 9 5.7. Study of diffusion by experimental techniques 131 5.7.1. Application of FTIR-ATR spectroscopy to diffusion in polymers 134 Chapter 6 6.1. Introduction 141 6.2. Experimental 141 6.2.1. Chemicals 141 6.2.2. Sample preparation and spectroscopic measurements 143 6.3. Results and discussion 145 6.3.1. Raman surface profile and SEM surface image of SPEES-'PES film 145 6.3.2. Comparison of dry and wet SPEES/PES spectra 150 6.3.3. Comparison of shape of water v(OH) and v(OD) bands in pure water and in polymer matrix 153 6.3.4. Diffusion of pure water in SPEES/PES 160 6.3.5. Sorption and desorption 171 Chapter 7 7.1. Introduction 187 7.2. Diffusion of water from aqueous ionic solutions 187 7.2.1. Experimental 188 7.2.2. Results and discussion 189 7.3. Effect of ionic concentration on diffusion of water 207 7.3.1. Experimental 207 7.3.2. Results and discussion 210 7.4. SPEES/PES-PVOH laminate 215 7.4.1. Experimental 215 7.4.2. Results and discussion 217 7.5. Effect of annealing temperature on SPEES/PES 223 7.5.1. Experimental 223 7.5.2. Results and discussion 223 Chapter 8 8.1. Introduction 229 8.2. Summary and conclusion 229 8.3. Future work 235 References Appendix I Appendix II 'How resplendent the luminaries o f knowledge that shine in an atom, and how vast the oceans o f wisdom that surge within a drop I' Baha'u'llah DECLARATION The work described in this thesis was carried out by the author in the Materials Research Institute, Sheffield Hallam University, between September 1993 and October 1996. The author declares that this work has not been submitted for any other degree. The work is original except where acknowledged by reference. Author: (Sohail Hajatdoost) Supervisor: (Professor Jack Yarwood) ACKNOWLEDGEMENTS My sincere and special thanks go to my supervisor Professor Jack Yarwood who has made indescribable contributions. His enthusiasm, interest and patience will be remembered for many years. It has been an honour for me to learn from his many skills throughout the past three years. I would further like to acknowledge Dr Peter Cardew, Dr Steven Spells, Dr Neil Everall, Professor Julia Higgins and Professor D. E. Irish for their help and advice. The collaboration work with Maurien Olsthoom is appreciated. I must also thank Sheffield Hallam University and NWW Acumem Limited for their financial support for my project. The encouragement, patience and real support of my dear parents throughout the final months of the project is always remembered and the hospitality, kindness and generosity of Mena is truly appreciated. All my friends within the group, Nigel, Reena, Bryan, Evangelos, Chris, Jason, Francis, Delphine, Peter, Carine, and Claudia will be remembered. CHAPTER 1 Introduction Molecular vibrations Anharmonicity Normal modes o f vibration Fourier Transform Infrared Spectrometry and Interferometry Advantages ofFTIR spectroscopy Attenuated Total Reflectance 1.1. Introduction to infrared spectroscopy Infrared, IR, radiation is electromagnetic radiation, in the wavelength range that is adjacent to and of lower energy than visible radiation. This region is divided in to smaller regions according to energetic proximity to the visible spectral region. This is summarised in table 1.1. IR region approximate range (cm-1) vibrational and/or rotational changes near-IR 14,000- 4,000 Some low-energy electron transitions as well as changes in vibrational and rotational levels mid-IR 4,000 - 400 Changes in fundamental vibrational levels of most molecules and thus it is of most use for chemical analysis far-IR 400 - 20 rotational changes occur in this region Table 1.1: Summary o f various regions o f infrared radiation In infrared spectroscopy, the observation time for a single vibrator is between 10‘13 to 10'15 seconds. This is important, because it controls the sort of information which can be obtained from this branch of spectroscopy as compared with some other spectroscopic 1 techniques.