A novel conceptual approach to gas‐responsive functionality, with the capability to tune the amphiphilic characteristics of existing waterborne polyurethanes (WPUs), via CO
2/N
2 bubbling in aqueous solution, is exploited. In this study, a series of functional WPUs are successfully prepared. These colloids exhibit high aqueous stability, excellent capability for emulsification/demulsification as a surfactant, and reversible hydrophilic/hydrophobic phase transition owing to reversible formation of carboxylic acid moieties induced by bubbling CO
2 gas. More interestingly, when carboxylated multiwalled carbon nanotubes (CNTs) are covalently incorporated into these WPUs, the CNT exhibits CO
2‐switchable amphiphilic behavior in a two‐phase mixture of
n‐butanol (BuOH)/deionized water, forming a stable hydrophobic CNT dispersion in BuOH upon CO
2 bubbling, and reversibly reverting to the previous hydrophilic CNT dispersion in water upon N
2 bubbling. With simple preparation and switchable amphiphilic properties, these CO
2‐responsive WPUs offer a paradigm for the development of multifunctional gas‐responsive polymers.
相似文献