The authors are most grateful to Jessica Bright, who worked tirelessly to support this project, to the staff at the Royal Society of Chemistry, to the many current students and postdoctoral fellows in our groups who read drafts of the chapters, and to our families for their patience and encouragement during the writing of this manuscript.

Our studies of CO₂-switchable materials over the past 16 years would not have been possible without the contributions of countless students, fellows, and visiting scientists, the support and facilities of our departments at Queen's University, the guidance from our collaborators and industrial partners, and the tireless efforts of the many people at GreenCentre Canada, Switchable Solutions, and Forward Water Technologies.

We also thankfully acknowledge the many agencies and donors who funded our research in this field, including but not limited to the Natural Sciences and Engineering Research Council of Canada, the Canada Research Chairs Program (PGJ), and the Ontario Research Chairs Program (MFC).