Effect of pyrolysis on microstructures made of various photoresists by two-photon polymerization: comparative study

Two-photon laser polymerization (TPP) is a state-of-the-art technology that allows for the submicron-resolution printing of freeform 3D objects to be harnessed in various applications, including physics, biology, medicine, and materials science. The TPP is based on using photosensitive polymeric materials that impose restrictions on the minimum feature size and limit the functionality of printed structures within the capabilities of polymers. One of the promising yet insufficiently studied methods for overcoming these limitations is pyrolysis–high-temperature annealing of polymer objects in an inert atmosphere. It may allow both to decrease the size of the objects and modify their chemical composition. Here, we compare the effect of pyrolysis on solid objects being tens of micrometers in size printed by TPP from three commercially available photoresists: IP-Dip, OrmoComp, and SZ2080. For the annealing temperatures of 450°C and 690°C in an argon atmosphere, we assessed the changes in size, chemical composition, and adhesion to the silicon wafer substrate. Our data may be promising for developing pyrolysis as a standard post-processing method for structures created via TPP technology.