Ice accretion can adversely impact many engineering structures in commercial and residential sectors. Although there are many reports of low-iceadhesion-strength materials, a scalable and durable deicing solution remains elusive, as ice detachment is dominated by interfacial toughness for large interfaces. In this work, durable metallic coatings based on Al-rich quasicrystalline alloys were prepared and applied on aluminum substrates using high-velocity oxyfuel thermal spray. X-ray diffraction patterns confirmed the quasicrystalline phases of the coating, and its largescale deicing capability was studied by evaluating the coating's ice detachment mechanics using long lengths of ice. A toughness-controlled regime of interfacial fracture was observed for ice lengths longer than ∼2 cm, and a low shear strength of ∼30 kPa was achieved for a 20 cm ice length. The metallic coatings exhibited excellent ice repellency even after being abraded, scratched, heated, UV-irradiated, and exposed to chemical contaminations, demonstrating promising durability for real-world, largescale ice removal.

The low temperature and high pressure tribological properties of polydimethylsiloxane brushes with ice are explored to demonstrate their feasibility as an exterior coating for an off-world cryobot. Successful deposition of the brushes on silicon and glass was confirmed with a contact angle hysteresis < 2° and a surface roughness below 1 nm. The friction factor of the brushes roughly doubled when the temperature was lowered from +20 °C to -20 °C, but it decreased by 55% when the normal force was increased from 0.5 N to 16 N. When sheared, adhered ice slid on the brushes at a shear stress around 21 kPa, and this did not increase with an additional normal pressure of up to 98 kPa. A glass rod coated with the brushes served as a cryobot surrogate and was frozen within cores of -10 °C ice 1 – 3 cm high. Weight attached to the rod enabled it to cleanly slide completely through the ice cores at the ambient -10 °C, i.e. without melting the ice. Together, these results indicate that polydimethylsiloxane brushes may be a feasible exterior coating for an off-world cryobot that would enable it to slide through the frozen surface of potentially life-harboring bodies such as Europa or Enceladus, avoiding the need to melt the entire cryobot’s exterior.

Mosquito-borne diseases such as dengue, chikungunya, and malaria have long been a health and economic burden in our society. Such illnesses develop after the pathogen, here arboviruses, are transmitted to humans by female mosquitoes during blood meals. In the case of dengue and chikungunya, such pathogens are transmitted to humans by infected Aedes aegypti females. Prior to feeding the insects rest on vertical surfaces. In this work, a surface roughness threshold was observed for live Aedes aegypti colonies, and below a root-mean-squared roughness of S q < 0.124 μm the mosquitoes were physically incapable of gripping vertical substrates. This roughness threshold was unaffected by surface wettability or relative humidity. The importance of topographical feature height was understood using a claw-hooking model considering friction. Local defects above this threshold allowed claw hooking to take place, emphasizing the importance of surface uniformity. An antimosquito coating was developed that reduced surface roughness below this threshold when it was applied to realistic surfaces such as wood, brick, wall laminates, and tile. Lowering the surface roughness below the threshold reduced the number of mosquitoes capable of landing on the surfaces by 100%: i.e., no mosquitoes were able to adhere to the treated surfaces. The ability to completely inhibit Aedes aegypti females from landing on surfaces represents a new vector-borne disease control strategy that does not suffer from the nontarget toxicity, resistance, or ecosystem disruption associated with conventional chemical control strategies.