  Growth of ice on surfaces poses a challenge for both organisms and for
devices that come into contact with liquids below the freezing point.
Resistance of some organisms to ice formation and growth, either in subtidal
environments (e.g. Antarctic anchor ice), or in environments with moisture and
cold air (e.g. plants, intertidal) begs examination of how this is
accomplished. Several factors may be important in promoting or mitigating ice
formation. As a start, here we examine the effect of surface texture alone. We
tested four candidate surfaces, inspired by hard-shelled marine invertebrates
and constructed using a three-dimensional printing process. We screened
biological and artifical samples for ice formation and accretion in submerged
conditions using previous methods, and developed a new test to examine ice
formation from surface droplets as might be encountered in environments with
moist, cold air. It appears surface texture plays only a small role in delaying
the onset of ice formation: a stripe feature (corresponding to patterning found
on valves of blue mussels, Crassostrea gigas, or on the spines of the Antarctic
sea urchin, Sterechinus neumayeri) slowed ice formation an average of 25%
compared to a grid feature (corresponding to patterning found on sub-polar
butterclams, Saxidomas). The geometric dimensions of the features have only a
small (~6%) effect on ice formation. Surface texture affects ice formation, but
does not explain by itself the large variation in ice formation and
species-specific ice resistance observed in other work. This suggests future
examination of other factors, such as material elastic properties and coatings,
and their interaction with surface pattern.
