Tailoring CO₂-Responsive Polymers and Nanohybrids for Green Chemistry and Processes

Stimuli-responsive materials are functional materials that can change their physical and chemical properties or perform specific functions in response to external stimuli. The use of these materials in chemical reactions and processes can make the production or operations controllable and repeatable (or recyclable), which may allow green chemistry and technologies with lower consumption of matter and energy. Among various stimuli-responsive materials, CO₂-responsive polymer materials are highly attractive because of their unique advantages of using CO₂ as a trigger in aspects of responding speed, contamination accumulation, operation scale, cost, and environmental friendliness, in addition to the characteristic capability to precisely regulate the response performance of polymers through manipulating their chain structures. In this review, we discuss the development of CO₂-responsive polymers and nanocomposites with designed performance from tailoring the polymer chain structures including functionalities, compositions, and topologies, as well as hybridizing with inorganic nanomaterials. Applications of these materials in fields of catalysis, nanoreactors, switchable surfactant/stabilizers, and separation are also summarized in detail. Our focus is on how the CO₂-responsive polymer materials with specific properties can be designed to reduce energy consumption and waste production. We believe that by tailoring the chain structures of CO₂-responsive polymer materials, customizing their properties, and hybridizing them with functional nanomaterials, they could be utilized in the fields of catalysis, colloids, separations, and others to enable greener and more energy-efficient processes.