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Waterborne Polyurethane Colloids with Sensitive CO 2 ‐Switchable Hydrophilic/Hydrophobic Properties
Author(s) -
Shieh YeongTarng,
Zeng ZiHau,
Cheng ChihChia
Publication year - 2018
Publication title -
macromolecular chemistry and physics
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.57
H-Index - 112
eISSN - 1521-3935
pISSN - 1022-1352
DOI - 10.1002/macp.201800247
Subject(s) - amphiphile , polymer , aqueous solution , carbon nanotube , chemical engineering , polyurethane , dispersion (optics) , materials science , polymer chemistry , aqueous two phase system , colloid , hydrophobic effect , pulmonary surfactant , phase (matter) , covalent bond , chemistry , organic chemistry , nanotechnology , copolymer , physics , optics , engineering
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.