Facilitating Large‐Scale Snow Shedding from In‐Field Solar Arrays using Icephobic Surfaces with Low‐Interfacial Toughness

Abstract

Large‐scale accrual of snow and ice on solar arrays in northern latitudes can cause significant power generation losses during winter. Depending on environmental conditions, snow can encompass a wide range in physical characteristics from dry snow (modulus ≈100 kPa and density ≈0.1 g cm−3) to bulk ice (modulus ≈8 GPa and density ≈0.9 g cm−3). This variation in snow morphology has made the development of a passive, broad‐spectrum, snow and ice‐shedding surface challenging. Here, the authors develop one of the first surfaces that simultaneously possesses both low‐interfacial strength (τ˄ice < 50 kPa) and toughness (Γice < 0.5 J m−2) with ice. These surfaces, fabricated via the addition of mobile polymer chains/oils to a thin polymeric coating, require extremely low detachment forces for ice, enabling its passive shedding at virtually any accretion length scale. Preliminary evidence that the new surfaces can shed different forms of snow and ice from field‐deployed solar arrays, over a range of subzero temperatures for several weeks, leading to significant increases in power generation is provided. The optically transparent surfaces are easily scalable and can be widely deployed by the solar industry in areas that see persistent snow. Other applications include automotive windshields, LIDAR covers for autonomous vehicles, and cold climate optical sensors.

Smart low interfacial toughness coatings for on-demand de-icing without melting

“…Zeng et al introduced a LIT coating comprised of porous PDMS that exhibited lower interfacial toughness and hydrophobicity with increasing porosity 47 . Dhyani et al fabricated transparent LIT PDMS and polyvinylchloride (PVC) coatings for photovoltaic applications, simultaneously demonstrating both a low interfacial toughness and ice adhesion strength 48 . Yu et al fabricated robust LIT coatings based on PTFE particle assemblies, where the interfacial toughness was maintained after repeated icing and de-icing cycles 49 .…”

Electro‐/Photo‐Thermal Promoted Anti‐Icing Materials: A New Strategy Combined with Passive Anti‐Icing and Active De‐Icing

“…Compared with electro-thermal heat techniques, solar energy as the renewable source is free and sustainable from nature. Recently, researchers investigated sun light (or artifical light) to replace electric power, and developed photo-thermal promoted AIM by combining passive AIM (i.e., SHSs, [106] lubricating surfaces, [107][108][109][110] and other icephobic surfaces [111,112] ) (Figure 7) with active photo-thermal heating with the help of various absorbers (i.e., Fe 3 O 4 , [107,108,[113][114][115] candle soot, [12,116] carbon nanotubes (CNTs), [89,90,112,[117][118][119][120][121][122][123][124][125][126] carbon nanofibers, [111] CNTs/Fe 3 O 4 @ poly(cyclotriphosphazene-co-4,4′-sulfonyldiphenol) (PZS), [127] cermet, [32] I 2 , [128] SiC, [129] polypyrrole (PPy), [98] melanin, [130] CNTs/SiO 2 , [131] Fe/candle soot, [106] Fe/Cu, [132] titanium nitride (TiN), [133,134] Ti 2 O 3 , [135] Au/TiO 2 , [66,136] Au/SiO 2 ,…”

“…Compared with electro‐thermal heat techniques, solar energy as the renewable source is free and sustainable from nature. Recently, researchers investigated sun light (or artifical light) to replace electric power, and developed photo‐thermal promoted AIM by combining passive AIM (i.e., SHSs, [ 106 ] lubricating surfaces, [ 107–110 ] and other icephobic surfaces [ 111,112 ] ) ( Figure ) with active photo‐thermal heating with the help of various absorbers (i.e., Fe 3 O 4 , [ 107,108,113–115 ] candle soot, [ 12,116 ] carbon nanotubes (CNTs), [ 89,90,112,117–126 ] carbon nanofibers, [ 111 ] CNTs/Fe 3 O 4 @poly(cyclotriphosphazene‐co‐4,4′‐sulfonyldiphenol) (PZS), [ 127 ] cermet, [ 32 ] I 2 , [ 128 ] SiC, [ 129 ] polypyrrole (PPy), [ 98 ] melanin, [ 130 ] CNTs/SiO 2 , [ 131 ] Fe/candle soot, [ 106 ] Fe/Cu, [ 132 ] titanium nitride (TiN), [ 133,134 ] Ti 2 O 3 , [ 135 ] Au/TiO 2 , [ 66,136 ] Au/SiO 2 , [ 137 ] reduced graphene oxide (rGO), [ 138 ] graphite, [ 139 ] SiO 2 /CuFeMnO 4 , [ 140 ] MXene, [ 141 ] and black engineered aluminum [ 142,143 ] ) (See Table 3 ). Generally, the absorption capacity of these absorbers differs from one to another, and the photo‐thermal effect usually occurs under different light wavelengths, such as solar radiation, [ 107 ] near infrared irradiation, [ 89,108,118,129 ] and infrared irradiation (See Table 3).…”

Superhydrophobic and Anti‐Icing Coatings Made of Hierarchically Nanofibrillated Polymer Colloids

“…The addition of an elastomeric binder has previously been shown to improve the hydrophobic and mechanical properties of nanofibrous 3D networks and has previously found application as icephobic coatings and nonwovens. [29][30][31][45][46][47] To explore SDC networks that might exhibit hydrophobic and anti-icing properties well-suited for applications requiring a more durable, yet porous, polymer material, [31,33] we chose to investigate PES SDCs and PES SDC/PDMS composites. PES SDCs nonwovens are highly elastic and exhibit good mechanical integrity as nonwovens evidenced by their being rolled cylindrically, folded, and bent while exhibiting high WCAs (>125°) (illustrated by the images in Figure 4a,b) While PS SDC sheets can similarly be handled, rolled, and folded, their decreased inter-fiber adhesion in the bulk network is more easily fractured with the application of tensile stress compared to PES and PVOH nonwovens (Figure 1).…”

“…[13][14][15][16][17][18][19][20] Coating architectures with hierarchical features both on the micro-and nano-scales have been found to maximize liquid repellency, facilitate droplet roll-off, delay ice nucleation in static water droplets, and, in some cases, reduce ice adhesion strength. [21][22][23][24][25][26][27][28][29][30][31][32][33][34] Chemically modified polymeric anti-icing coatings are often limited in their scalability and can be subject to fouling of the coating or mechanical abrasion, which leads to reduced functionality. [35] One common strategy to mitigate such deterioration is to create thicker, porous coatings from polymers with low surface energy as opposed to functionalizing a thin hydrophobic layer on the surface.…”