Session 4 - Oral 2
Onion inspired anti-hydrate surfaces
Feng Wang, Jianying He, Zhiliang Zhang
Nanomechanical Lab, Department of Structural Engineering, Norwegian University
of Science and Technology (NTNU), Trondheim 7491, Norway.
gas-hydrate formation and the subsequent gas-pipeline plugging is of crucial
importance during the exploration and transportation of deep-water resources.
Passive anti-hydrate surfaces that can inhibit hydrate formation directly on
pipe walls or lower the adhesion between hydrates and solids without external
force or energy inputs are desired. In this work, the onion film that consists of monolayer epidermal
cells was found to be accountable for the low adhesion of onion bulb scales to
solids. Firstly, the sub-surface porous structures led to interface stiffness
inhomogeneity and initiated interface cracks. Secondly, the surface cuticle
layer acted as hydrophobic lubricant for lowing the adhesion. Inspiring by the
onion film with low adhesion to solids, an elastomer film with smooth surface
and sub-surface micropatterns was introduced. With the onion inspired film, the
cyclopentane hydrate adhesion strength on glass was
decreased dramatically from 95 kPa to 4.7 kPa. Importantly, the hydrate adhesion strength on the onion inspired
surface maintained super low (8.7 kPa) after
20 cyclic tests. Integrating a regenerable artificial cuticle layer enabled even lower
hydrate adhesion (2.9 kPa) on this film. The onion inspired surface therefore is
promising for future hydrate mitigation.
Keywords: Gas hydrate, onion film, hydrate adhesion
strength, anti-hydrate surface.