Controlling Young’s modulus of polymerized structures fabricated by direct laser writing

We demonstrate that Young’s modulus of polymerized microstructures in both air and liquid can be controlled by changing the writing velocity of the femtosecond laser two-photon polymerization, which is crucial for many practical applications. For the zirconium/silicon inorganic/organic hybrid sol–gel, the Young’s modulus for dry polymerized micro-cantilevers in air can be adjusted from 5.5 to 9.4 GPa by varying writing velocity from 600 to 200 μm/s, and it also can be controlled in liquid, which is four orders smaller than in air. To characterize the Young’s modulus in liquid, we propose a simple method by measuring non-adhered lengths of the arc-shaped or s-shaped polymerized micro-cantilevers after drying in air.