Carbon Dioxide‐Switchable Chitosan/Polymer Composite Nanogels

Carbon dioxide (CO 2 )‐switchable composite nanogels are composed of biopolymer chitosan (CS) and synthetic polymer poly [N‐(3‐(dimethylamino) propyl) methacrylamide] (PDMAPMA). CS/PDMAPMA composite nanogels (CPCNGs) are fabricated in the solution of chitosan by soap‐free emulsion polymerization using N‐(3‐[dimethylamino] propyl) methacrylamide (DMAPMA) as the monomer and N , N ‐methylenebis (acrylamide) (BIS) as the cross‐linker. The scanning electron microscope (SEM) results indicate that the nanogels are spherical nanoparticles with a diameter of about 50 nm. After purging with CO 2, the original creamy‐white latex becomes a clear solution. While purging with N 2 , the clear solution is returned to the original latex state. Introduction of chitosan in nanogels remarkably enhances their CO 2 sensitivity. In additional, the SEM results also suggest that phase transition behavior occurs through CO 2 and N 2 bubbling. The initial state of nanogels can be easily recovered by “washing off” the trigger gas with N 2 .