In this project we will explore ion transport in conjugated polymers. Research during this project was centered on subsequent topics: 1. Driving mechanisms (migration and diffusion) for ion transport. 2. Relationship between ions, charge, and volume change. 3. Link between experimental situations (voltage, film thickness, ion barrier thickness, swelling of polymers, electrolyte, and temperature) on ion transport. 4. Creating a physics-based model and performing numerical simulations for ion transport in conjugated polymers. The outcomes of this project had been abbreviated primarily in three articles. Cation ingress in the polymer was exhibited by means of phase front propagations which were created by electrochromism. Migration was identified to dominate ion ingress evidenced by a linear relationship between phase front velocity and reduction potentials. We also did experimental research of ion transport in PPy(DBS). Apart from phase front propagation velocity and broadening, current data and actuation strains of PPy(DBS) were also gathered. Evaluations among these data gave much more information of cation transport in PPy(DBS). Diffusion of ions in PPy(DBS) was discovered to be non-Fickian diffusion that has not been a part of models of the literature. We found Cation egress to be independent with applied potentials, indicating a diffusion controlled procedure, while cation ingress was observed to be dominated by migration. This particular difference between cation ingress and cation egress hasn’t been recognized prior to this dissertation. The consequence of polymer swelling on cation ingress was characterised the very first time, which indicated an exponential relationship between ion mobility and ion concentration…..
This video is about Conjugated Polymers. Click the play button to get an overview of conjugated polymers.
Contents
Chapter 1 Introduction
1.1 Conjugated Polymer Actuators
1.2 Doping of Conjugated Polymers
1.2.1 Conjugated Polymer Backbones
1.2.2 Doping of Conjugated Polymers
1.2.3 Doping Induced Property Change of Conjugated Polymers
1.3 Contributors to Volume Change of Conjugated Polymers
1.3.1 Ion Transport
1.3.2 Solvent Transport
1.3.3 Chain Conformation Relaxation
1.4 PPy(DBS): a Model System Used in this Dissertation
1.5 Operation of Conjugated Polymer Actuators
1.5.1 Operation Setup
1.5.2 Voltage and Current of the Working Electrode
1.5.3 Control Methods
1.6 References
Chapter 2 Aim of Current Study and Organization of this Dissertation
2.1 Aim of Current Study
2.2 Organization
Chapter 3 Visualizing Ion Currents in Conjugated Polymers
3.1 Introduction
3.2 Experimental
3.3 Results
3.3.1 Experimental Results
3.3.2 Simulation Results
3.4 Conclusions
3.5 Acknowledgements
3.6 References
Chapter 4 Charge Transport in Conjugated Polymers: Part 1. ExperimentalResearch of PPy(DBS)
4.1 Introduction
4.2 Experimental Methods
4.2.1 Device Fabrication
4.2.2 Electrochemical Cycling
4.2.3 Out-of-Plane Strain Measurement
4.2.4 Phase Front Analysis
4.2.5 Current Correction during Chronoamperometry
4.3 Results
4.3.1 Electrochemical Reduction
4.3.2 Electrochemical Oxidation
4.3.3 Intensity, Charge, and Strain
4.4 Discussion
4.5 Summary and Conclusions
4.6 Acknowledgements
4.7 References
Chapter 5 Charge Transport in Conjugated Polymers: Part 2. Modeling andSimulation Results
5.1 Introduction
Part A: Model Development
5.2 Model Overview
5.3 Modeling Methods
5.3.1 Model Properties
5.3.2 Reducing Model Complexity
5.4 Numerical Methods
5.4.1 General
5.4.2 2-D Simulations
5.5 Results 1: Base Case Model and Variations
5.5.1 Base Case Simulation Results
5.5.2 2-D Confirmation of 1-D Results
5.5.3 Parameter Variation
5.6 Results 2: Increased Model Complexity
5.6.1 Nonconstant Coefficients
5.6.2 Diffusion and Migration
5.6.3 Diffusion Only
5.6.4 Addition of the Electrolyte
5.7 Summary of Model Development Results
Part B: Full Model Results/Predictions
5.8 Results 3: Model Predictions
5.8.1 Effect of Electrolyte Concentration
5.8.2 Oxidation of a Cation-Transporting Material
5.8.3 Uncovered Thin Film
5.8.4 Anion-transporting Conjugated Polymers
5.8.5 Discussion of Model Predictions
5.9 Conclusions
5.10 Acknowledgements
5.11 References
Chapter 6 Summary of Scientific Contributions
Chapter 7 Future Work
Appendix244
1.1 Supplementary Experimental Results
1.1.1 Reduction
1.1.2 Oxidation
1.1.3 Effect of Electrolyte Concentration
1.1.4 Effect of Temperature
1.1.5 Effect of Ion Barrier Thickness
1.1.6 Effect of PPy Thickness
1.1.7 Effect of Ion Type
1.2 Supplementary Modeling and Simulation Results
1.2.1 Modeling and Theoretical Analysis………