mbnu FY2021 Annual Report 3.1.5 A

Fig. 5: A typical dispensing process. (A) A liquid bridge of height H connecting the nozzle of radius R_n and the substrate. (B) Retracting the nozzle to a height H >> H_c above the critical height H_c destabilizes the liquid bridge and causes it to thin under surface tension. (C) For viscoelastic liquid bridges, nozzle retraction creates satellite droplets and a long capillary tail, which may contaminate the substrate. (D) By applying torsion to a stable viscoelastic liquid bridge, an indent propagates toward the bridge center, leading to breakup even at H < H_c.