Visible Light Degradable Acridine-Containing Polyurethanes in an Aqueous Environment

Lightdegradable polymers hold significant promise in a wide rangeof applications including the fabrication of optically recyclablematerials, responsive coatings and adhesives, and controlled drugdelivery. Here, we report the synthesis of polyurethanes that canbe degraded under irradiation of visible light (& LE;450 nm) fromcommercial LED (3-15 W) light sources. The photolysis occursin an aqueous environment via photocleavage of an acridine moietyincorporated within the backbone of the polymer chains. Analysis ofthe quantum yield as a function of wavelength reveals highly efficientphotoreactivity at up to 440 nm activation, which is red-shifted comparedto the UV-vis absorbance of the chromophore. The potentialof our chemical system in biomaterials is demonstrated by the fabricationof an in situ forming hydrogel that can be degraded by visible light.