Natalie L Benbow1, Jessie L Webber1, Piotr Pawliszak1, Damien A Sebben2, Sam Karpiniec3, Damien Stringer3, Mark J Tobin4, Jitraporn Vongsvivut4, Marta Krasowska5, David A Beattie6. 1. Future Industries Institute, University of South Australia, Mawson Lakes, South Australia 5095, Australia; School of Information Technology and Mathematical Sciences, University of South Australia, Mawson Lakes, South Australia 5095, Australia. 2. Future Industries Institute, University of South Australia, Mawson Lakes, South Australia 5095, Australia. 3. Marinova Pty Ltd, Cambridge, TAS, Australia. 4. Infrared Microspectroscopy Beamline, ANSTO Australian Synchrotron, Clayton, Victoria 3168, Australia. 5. Future Industries Institute, University of South Australia, Mawson Lakes, South Australia 5095, Australia; School of Information Technology and Mathematical Sciences, University of South Australia, Mawson Lakes, South Australia 5095, Australia. Electronic address: Marta.Krasowska@unisa.edu.au. 6. Future Industries Institute, University of South Australia, Mawson Lakes, South Australia 5095, Australia; School of Information Technology and Mathematical Sciences, University of South Australia, Mawson Lakes, South Australia 5095, Australia. Electronic address: David.Beattie@unisa.edu.au.
Abstract
HYPOTHESIS: Odd-even effects in polysaccharide polyelectrolyte multilayers influence their hydration content and the chemical environment of the water within them. EXPERIMENTS: Polysaccharide polyelectrolyte multilayers (PEMs) composed of pharmaceutical grade fucoidan and chitosan were studied under confinement using synchrotron FTIR microspectroscopy at increasing pressure, in order to isolate and measure infrared spectra of water within the PEM, without interference from bulk water. Complementary studies of the PEMs were carried out using lab-based in situ attenuated total reflectance Fourier transform spectroscopy (ATR FTIR) and quartz crystal microbalance with dissipation monitoring (QCM-D), as well as zeta potential measurements, to determine the quantity of adsorbed polymer, hydration content, film thickness, viscoelastic properties and surface charge during layer-by-layer deposition. FINDINGS: The hydration of the PEM followed a saw-tooth profile, known as the odd-even effect, where the film increased hydration with fucoidan adsorption and dehydrated/densified with chitosan adsorption. The water structure within the film showed a lower degree of hydrogen bonding than water in the bulk electrolyte. However, the water structure/environment was independent of the terminating layer of the PEM, in spite of the alteration in percentage hydration water, indicating only a partial proof of the initial hypothesis for this multilayer system (hydration amount changes, hydration water environment does not).
HYPOTHESIS: Odd-even effects in polysaccharide polyelectrolyte multilayers influence their hydration content and the chemical environment of the water within them. EXPERIMENTS: Polysaccharide polyelectrolyte multilayers (PEMs) composed of pharmaceutical grade fucoidan and chitosan were studied under confinement using synchrotron FTIR microspectroscopy at increasing pressure, in order to isolate and measure infrared spectra of water within the PEM, without interference from bulk water. Complementary studies of the PEMs were carried out using lab-based in situ attenuated total reflectance Fourier transform spectroscopy (ATR FTIR) and quartz crystal microbalance with dissipation monitoring (QCM-D), as well as zeta potential measurements, to determine the quantity of adsorbed polymer, hydration content, film thickness, viscoelastic properties and surface charge during layer-by-layer deposition. FINDINGS: The hydration of the PEM followed a saw-tooth profile, known as the odd-even effect, where the film increased hydration with fucoidan adsorption and dehydrated/densified with chitosan adsorption. The water structure within the film showed a lower degree of hydrogen bonding than water in the bulk electrolyte. However, the water structure/environment was independent of the terminating layer of the PEM, in spite of the alteration in percentage hydration water, indicating only a partial proof of the initial hypothesis for this multilayer system (hydration amount changes, hydration water environment does not).
Authors: Jessie L Webber; Rashin Namivandi-Zangeneh; Sławomir Drozdek; Kazimiera A Wilk; Cyrille Boyer; Edgar H H Wong; Bronwyn H Bradshaw-Hajek; Marta Krasowska; David A Beattie Journal: Sci Rep Date: 2021-01-18 Impact factor: 4.379