A Linearly Deformable Pneumatic Scalable Microgripper for Universal Mid-Air Micromanipulation

The manipulation of microscale components with complex shape like semiconductors, 3D printed microparts, and optical lenses, remains challenging due to strong surface forces and limitations of existing methods. A 3D-printed soft pneumatic microgripper capable of rectilinear deformation is presented in this paper. It addresses these challenges through a concave design with two operational modes (snap and continuous) and an integrated adhesion-reducing mask. Fabricated with IP-PDMS two-photon polymerisation 3D printing, the microgripper achieves a 40  $\mu m$ minimum operation diameter and demonstrates a substrate-free release force as low as 11.1 nN with an adhesion switching ratio of 373 in the normal direction. Combined with rigid alignment, the device enables universal pick-and-place over a range of micro-objects and mid-air transition of ultralight components (≈1.14  $\mu g$ ) in confined spaces. With over 30000 actuation cycles without performance degradation, this scalable design can execute complex manipulation tasks through a multi-gripper system as demonstrated.