CO2 permeability control in 3D printed light responsive structures

Azobenzene cromophores are proposed as functional dyes for the development of smart DLP-3D printable formulations. Two different azo molecules have been tested for the fabrication of membranes; taking advantage of the photoisomerization of these compounds, light induced changes in CO2 permeability have been studied showing a great increase of gas transmission upon green light irradiation. The investigations showed a linear increase of permeability with the increase of laser intensity, enabling a fine control of gas permeation. Moreover, these materials showed selectivity toward different gases, enabling a great increase of permeation upon laser irradiation for CO2 but not for O-2. The use of the dye during the DLP printing process is necessary to confine the light inside the exposed layer allowing a precise printability without over-exposures; in this way complex architectures can be built and, at the same time, the choice of a molecule with intrinsic functionality transfers this functional property to the object. In the present study 3D structures presenting light triggered CO2 permeability have been built; as a proof of concept a smart 3D photocontrollable valve has been produced. (C) 2019 Elsevier Ltd. All rights reserved.