Morphology and Dynamics of Bottlebrush Polymers

ISBN-13: 9783030833817 / Angielski / Miękka / 2022

Karin J. Bichler

Opis

This thesis makes significant advances to the understanding of bottlebrush polymers. While bottlebrushes have received much attention due to the recent discovery of their unprecedented properties, including supersoftness, ultra-low viscosity, and hyperelasticity, this thesis is the first fundamental investigation at the molecular level that comprises structure and dynamics. Neutron scattering experiments, detailed within, reveal spherical or cylindrical shapes, instead of a random coil conformation. Another highlight is the analysis of the fast dynamics at the sub nm-length scale. The combination of three neutron spectrometers and the development of a new analysis technique enabled the calculation of the mean-square displacement over seven orders of magnitude in time scale. This unprecedented result can be applied to a broad class of samples, including polymers and other materials. The thesis is accessible to scientists from other fields, provides the reader with easily understandable guidelines for applying this analysis to other materials, and has the potential to make a significant impact on the analysis of neutron scattering data.

Spis treści

Table of Contents

Acknowledgements ......................................................................................................................... ii

Abstract ........................................................................................................................................... v

1. Introduction ............................................................................................................................. 1

2. Theory ..................................................................................................................................... 8

2.1 Polymer ........................................................................................................................... 8

2.2 Neutron Scattering ........................................................................................................ 17

2.3 Dielectric Spectroscopy ................................................................................................ 25

2.4 Fast Field Cycling (FFC) Relaxometry ........................................................................ 28

3. Experimental Techniques...................................................................................................... 34

3.1 Small-Angle Neutron Scattering (SANS) ..................................................................... 34

3.2 Quasi-Elastic Neutron Scattering (QENS) .................................................................... 37

3.3 Dielectric Spectroscopy ................................................................................................ 43

3.4 Fast Field Cycling (FFC) Relaxometry ........................................................................ 44

4. Morphology........................................................................................................................... 48

4.1 Data Analysis ................................................................................................................ 48

4.2 Results and Discussion ................................................................................................. 53

5. Dynamics .............................................................................................................................. 85

5.1 Data Analysis ................................................................................................................ 85

5.2 Results and Discussion ................................................................................................. 93

6. Summary and Conclusion ................................................................................................... 147

Appendix A. Supplementary Data for the Chapter Morphology ................................................ 152

Appendix B. Supplementary Data for the Chapter Dynamics .................................................... 154

Appendix C. Publication Agreement and Permission................................................................. 175

References ................................................................................................................................... 176

Vita .............................................................................................................................................. 191

O autorze

Karin Bichler is a postdoctoral researcher in the Department of Chemistry at Louisiana State University, Baton Rouge, USA, focusing on structure and dynamics of polymers. She received her Bachelor of Science and Master of Science in Physics from the University of Regensburg, Germany in 2014 and 2016 respectively. After research experiences at Material Physics Center, San Sebastián, Spain and Louisiana State University, Baton Rouge, USA she decided to pursue a PhD in Physics in the Department of Physics and Astronomy at Louisiana State University, which was awarded in 2020.