MALMÖ UNIVERSIT Y HEAL TH AND SOCIET Y DISSERT A TION 20 1 4:3 ANT ON F A GERS TR ÖM MALMÖ UNIVERSIT Y 20 1 4 MALMÖ HÖGSKOLA 205 06 MALMÖ, SWEDEN WWW.MAH.SE isbn 978-91-7104-576-8 (print) isbn 978-91-7104-575-1 (pdf) issn 1653-5383 EFFECT S OF SURF A CT ANT ADJUV ANT S ON PL ANT LEAF CUTICLE B ARRIER PR OPERTIES
ANTON FAGERSTRÖM
EFFECTS OF SURFACTANT
ADJUVANTS ON PLANT LEAF
CUTICLE BARRIER PROPERTIES
Malmö University
Health and Society, Doctoral Dissertation 2014:3
© Copyright Anton Fagerström 2014
Front illustration: Mattias Olsson, Clivia leaf and index finger against a Brazilian cornfield backdrop.
ISBN 978-91-7104-576-8 (print) ISBN 978-91-7104-575-1 (pdf) ISSN 1653-5383
ANTON FAGERSTRÖM
EFFECTS OF SURFACTANT
ADJUVANTS ON PLANT LEAF
CUTICLE BARRIER PROPERTIES
Malmö University, 2014
Faculty of Health and Society
Department of Biomedical Sciences
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CONTENTS
ABSTRACT ... 9
POPULÄRVETENSKAPLIG SAMMANFATTNING ... 11
LIST OF PUBLICATIONS ... 13
ABBREVIATIONS AND SYMBOLS ... 15
INTRODUCTION ... 17
Background ... 17
The plant leaf cuticle ... 18
Cuticle wax ... 19
Role of surfactants in agricultural applications ... 19
Diffusion in the cuticle ... 20
Softening/Structural effects ... 20
The scientific questions in this thesis and their relevance ... 20
EXPERIMENTAL TECHNIQUES AND CONSIDERATIONS ... 23
Diffusion cells ... 23
Quartz Crystal Microbalance with Dissipation ... 27
Small and Wide Angle X-ray Diffraction ... 29
Differential Scanning Calorimetry (DSC) ... 31
Isothermal Sorption Calorimetry ... 32
Polarized light optical microscopy (PLOM) ... 32
Scanning Electron Microscopy (SEM) ... 33
High Performance Liquid chromatography (HPLC-UV) ... 33
Gas chromatography with Mass spectrometry (GC-MS) ... 33
RESULTS AND DISCUSSION ... 35
Cuticle characterization ... 35
Stomata and cuticle thickness ... 35
Cuticle thermotropic phase behaviour ... 36
Surfactant structural effects on isolated cuticle ... 38
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Model wax composition ... 40
C22H45OH/C32H66 ... 42
Model wax - water phase behaviour ... 44
C22H45OH/H2O ... 45
C32H66/H2O... 47
C22H45OH/C32H66/H20 ... 47
Model wax validation ... 49
Surfactant solutions ... 50
Surfactant water sorption ... 50
Surfactant solutions ... 52
Formulations design and dynamics ... 53
Effects of surfactants on the cuticle ... 56
Surfactant structural effects on isolated cuticle ... 56
Surfactant induced changes in cuticle model wax I: Phase behaviour ... 57
Thermotropic phase transitions ... 57
Surfactant induced changes in cuticle model wax II: Fluidity ... 59
Continuous QCM-D experiments ... 59
Pulsed QCM-D experiments ... 60
Wax film rheology ... 63
Diffusion in the cuticle ... 66
Cuticle membrane ... 66
Membrane partition ... 66
Membrane permeability ... 67
Solute distribution and diffusion ... 67
CONCLUDING REMARKS AND FUTURE OUTLOOK ... 73
ACKNOWLEDGEMENTS ... 76
REFERENCES ... 77
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LIST OF PUBLICATIONS
This thesis is based on the following papers, which are cited in the text by their Roman numerals. The papers are appended in the end of the thesis.
I. Fagerström A, Runnsjö A, Kocherbitov V, Engblom J.
Plant leaf
cuticle structure – effects of temperature, relative humidity, and
surfactant absorption.
Manuscript.II. Fagerström A, Kocherbitov V, Westbye P, Bergström K,
Mamon-tova V, Engblom J.
Characterization of a plant leaf cuticle model
wax, phase behaviour of model wax - water systems.
Thermochim. Acta, 571 (2013) 42– 52.III. Fagerström A, Kocherbitov V, Westbye P, Bergström K, Arnebrant
T, Engblom J.
Surfactant softening of plant leaf cuticle model wax
– a Differential Scanning Calorimetry (DSC) and Quartz Crystal
Microbalance with Dissipation (QCM-D) study.
J. Colloid Interface Sci., 426 (2014) 22-30.
IV. A. Fagerström A, Kocherbitov V, Ruzgas T, Westbye P, Bergström
K, Engblom J.
Effects of surfactants and thermodynamic activity
of model active ingredient on transport over plant leaf cuticle.
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MALMÖ UNIVERSIT Y HEAL TH AND SOCIET Y DISSERT A TION 20 1 4:3 ANT ON F A GERS TR ÖM MALMÖ UNIVERSIT Y 20 1 4 MALMÖ HÖGSKOLA 205 06 MALMÖ, SWEDEN WWW.MAH.SE isbn 978-91-7104-576-8 (print) isbn 978-91-7104-575-1 (pdf) issn 1653-5383 EFFECT S OF SURF A CT ANT ADJUV ANT S ON PL ANT LEAF CUTICLE B ARRIER PR OPERTIES
