Photocurable Foam\nfor Three-Dimensional-Printed Porous\nStructures

In this research, a foam three-dimensional (3D) printing\nmethod\nusing digital light processing (DLP) technology was developed to fabricate\n3D-printed porous structures. To address the challenges in preparing\nDLP precursor foam fluid, we designed a specialized foaming device.\nThis device enables the precursor solution to be blended with air,\nresulting in a stable foam precursor with an adjustable air/liquid\nfraction and suitable fluidity, crucially enhancing the gas–liquid\ncontact time for the printing process. By manipulation of fluid flow\nrates, cycle counts, and gas/liquid ratios, one can easily prepare\nuniform foams with precise control over the pore size and porosity.\nTo avoid significant volume reduction during ultraviolet (UV) curing,\nnanoparticle fillers were introduced into the network to prevent collapse\nof the foam structure. Furthermore, the inclusion of an UV absorber\nenhanced the quality of the printing process by addressing the limitations\nassociated with particle scattering and reflection. The DLP process\ncan readily fabricate intricate structures, featuring a planar resolution\nbelow 30 μm and a printing accuracy of less than 1%. Several\nexamples were also demonstrated to highlight the advantages of this\ntechnology and its ability to directly print custom foam structures,\nthereby saving time and material resources.