Fig. 1 Mechanisms responsible for low ice adhesion. (A) PDMS-based coatings having low or high ρCL, with or without interfacial slippage. (B) Relationship between ρCL and τice for coatings without interfacial slippage. Error bars are 1 SD, and the best fit is found using the method proposed by York et al. (44). The slope is 0.51 ± 0.04. (C) Variation of τice with ρCL for coatings with interfacial slippage. The best-fit slope is 1.01 ± 0.03. (D) Ice-reducing potential I* as a function of ρCL. Error bars are 1 SD, and for the best-fit curve shown, R2 = 0.89.
Fig. 2 Force versus time curve analysis. (A and B) Force versus time curves for a lubricant (PMHS oil) and lubricated (coating R) surfaces. The number next to each curve is the order in which the testing was performed. (C) Representative surfaces from fig. S1B, where the ice unadheres by interfacial cavitation. Note the abrupt drop in force once the ice has detached. Depending on the cross-link density, the ice adhesion can be low or high, but the mechanism for detachment remains the same. (D) The FPU (coating ZZ), which has no uncross-linked chains, causes ice to detach by interfacial cavitation, which results in high but consistent ice adhesion values. (E) In contrast, the PU coating (ρCL = 33 ± 1 mol/m3, 15 wt % safflower oil) shows interfacial slippage. Note the persistence of a nonzero sliding force long after the ice has moved from its original location. Comparing (A) to (E), it is apparent that lubricated surfaces lose their oily layer quite rapidly, transitioning to high ice adhesion surfaces. (F) In contrast, varying the cross-link density on surfaces exhibiting interfacial slippage, the τice values can also be low or high, but the mechanism for detachment remains the same.
Fig. 3 Comparison between interfacial slippage and lubrication. (A) Variation of τice with the number of icing/deicing cycles. See Materials and Methods for a description of each coating’s fabrication. The values of τice for both the lubricant and the lubricated systems increase with an increasing number of icing/deicing cycles (see Fig. 2, A and B, for force versus time curves). In comparison, there is no change in τice values for the surfaces with interfacial slippage over multiple icing/deicing cycles. (B) Variation in τice with oil viscosity. Values of τice for lubricated surfaces strongly depend on the oil viscosity and follow a typical Stribeck relationship (32). In comparison, the values of τice for surfaces with interfacial slippage are markedly independent of viscosity (coatings BH, BI, BJ, and BK in Table 1). (C) AFM phase images and optical micrographs of the PU coating with 15 wt % safflower oil. The surface does not have a lubricating oil layer. Note that the AFM phase image looks equivalent to the PU coating without oil (fig. S4C). (D) AFM phase images and optical micrographs of the PU coating with 10% silicone oil. The lubricating oil layer is clearly visible on the surface.
Fig. 4 Superhydrophobic and icephobic surfaces. (A) Droplets of water placed on icephobic PDMS pillars (coating I in Table 1) display superhydrophobicity, with
= 165°/161° and a low roll-off angle of 3° (inset). For 20 successive icing/deicing cycles on such surfaces, we measured τice = 26 ± 3 kPa. Such surfaces effectively repel liquid water through minimizing the solid-liquid contact area and solid ice through low ρCL and interfacial slippage. The differing mechanisms allow the surface to remain icephobic even after the surface is fully frosted. (B and C) SEM micrograph of the icephobic pillars before and after ice adhesion testing. The pillars are not removed during ice adhesion testing.Fig. 5 Durability of the different icephobic coatings developed in this work. (A) Outdoor testing of a PDMS-based coating (coating NN; see Table 1) for 4 months during winter 2014. On 12 Febuary, the uncoated panel was covered with a ~7-mm layer of glaze, the type of ice with the strongest adhesion (1). No ice had accreted on the coated panel. On 4 March, snow followed a night of freezing rain, which completely covered the uncoated panel. The coated panel only had a small amount of accreted ice remaining. (B) Half-coated license plate during outdoor winter 2013 testing, with ice only accreted on the uncoated side. (C) Mechanical abrasion of three different icephobic coatings. The PDMS (coating NN) and lubricated PU (coating CC) were easily damaged and delaminated within 20 abrasion cycles, whereas the PU with interfacial slippage (coating CB) survives over 5000 cycles while maintaining low ice adhesion. (D) Comparison of coatings in this work with other state-of-the-art icephobic surfaces. Also, additional durability characterizations are presented for the PU coating with interfacial slippage. For details on each coating and test configuration, see Materials and Methods.
- Table 1 A library of icephobic surfaces.
The coating fabrication methodology and resulting ice adhesion strengths, cross-link densities, and water contact angles for all the samples fabricated in this work. SG, Sylgard; SO, silicone oil; PS, polystyrene; PIB, polyisobutylene; PFPE, perfluoropolyethers; FPU, fluorinated polyurethane polyols; PMPS, polymethylphenyl siloxane; UVA, ultraviolet A; RT, room temperature; NS, no slippage (no oil is added to the coating); IS, interfacial slippage (miscible oil has been added but no lubricating liquid layer forms) [confirmed by atomic force microscopy (AFM), optical microscopy, and the shape of the force versus time curves]; L, lubricated [excess oil (either intentionally or otherwise) is added to the coating, forming a thick lubricating layer] (confirmed using the same methods as for interfacial slippage).
Polymer
baseNonreactive
oilwt % Reactive
oilwt % Cure
(°C/hour)ρCL
(mol/m3)τice
average (kPa)τice
min.
(kPa)τice
max.
(kPa)Type θadv/θrec
(°)A SG 184 10:1 — — — — 150/24 307±8 264 245 340 NS 120/94 B SG 184 10:1 — — — — 80/2 333±45 47 36 57 IS 131/26 C SG 184 20:1 — — — — 80/2 112±1 178 147 251 NS 129/45 D SG 184 4:1 — — — — 80/2 33±45 89 42 165 IS 127/36 E SG 184 3:1 — — — — 80/2 268±2 15 6 29 L 122/76 F SG 184 2:1 — — — — 80/2 222±9 14 6 23 L 118/77 G SG 184 5:2 — — — — 80/2 267±21 16 8 26 L 112/100 H SG 184 1:1 — — — — 80/2 162±5 14 6 29 L 112/89 I SG 184 10:1 100-cP SO 25 — — 80/2 219±13 35 26 56 IS 123/89 J SG 184 10:1 100-cP SO 50 — — 80/2 72±11 87 40 120 IS 114/94 K SG 184 10:1 100-cP SO 75 — — 80/2 — 55 30 71 IS 114/94 L SG 184 10:1 — — PMHS 25 80/2 215±10 10 1.0 31 L 105/103 M SG 184 10:1 — — PMHS 50 80/2 75±13 67 31 121 IS 118/101 N SG 184 10:1 — — PMHS 75 80/2 — 17 4.9 39 L 121/102 O SG 184 1:1 100-cP SO 25 — — 80/2 32±2 173 58 237 IS 124/86 P SG 184 1:1 100-cP SO 50 — — 80/2 13±2 46 17 74 IS 124/82 Q SG 184 1:1 100-cP SO 75 — — 80/2 — 18 0.15 47 IS 104/103 R SG 184 1:1 — — PMHS 25 80/2 102±5 17 1.0 40 L 125/104 S SG 184 1:1 — — PMHS 50 80/2 14±4 6 0.7 30 L 106/105 T SG 184 1:1 — — PMHS 75 80/2 — 9 0.35 31 L 105/103 U SG 184 10:1 100-cP SO 25 PMHS 25 150/24 536±97 64 50 78 IS 119/95 V SG 184 10:1 100-cP SO 15 PMHS 15 80/2 — 31 1.0 137 L 108/104 W SG 184 10:1 100-cP SO 10 PMHS 10 150/24 459±9 74 40 116 IS 123/90 X SG 184 10:1 — — PMHS 10 80/2 283±9 37 4.0 71 IS 114/100 Y SG 184 10:1 — — PMHS 10 150/24 284±41 173 122 234 NS 121/78 Z SG 184 10:1 — — PMHS 20 80/2 197±4 45 19 82 IS 109/105 AA SG 184 10:1 — — PMHS 20 150/24 348±28 64 34 92 IS 118/93 BB SG 184 10:1 — — PMHS 25 150/24 452±9 302 275 346 NS 103/84 CC SG 184 10:1 100-cP SO 25 PMHS 15 150/24 405±27 58 41 73 IS 112/104 DD SG 184 10:1 100-cP SO 20 PMHS 20 80/2 107±2 37 9.1 67 IS 109/100 EE SG 184 10:1 100-cP SO 25 PMHS 25 80/2 150±8 35 5.1 77 IS 116/99 FF SG 184 10:1 100-cP SO 25 PMHS 10 150/24 290±25 41 24 55 IS 112/108 GG SG 184 10:1 5-cP SO 25 — — 80/2 181±5 145 109 178 IS 121/90 HH SG 184 10:1 1000-cP SO 25 — — 80/2 153±7 45 33 53 IS 100/85 II SG 184 10:1 10000-cP SO 25 — — 80/2 67±2 81 13 226 L 120/104 JJ SG 184 10:1 SO AP 1000 25 — — 80/2 216±3 66 12 171 L 113/78 KK SG 527 1:1 — — — — 150/24 0.68‡ 14 7.6 25 NS 130/89 LL 1:9 SG 527:184 100-cP SO 25 — — 150/24 182±11 14 7.3 18 IS 112/103 MM 1:3 SG 527:184 100-cP SO 25 — — 150/24 123±2 10 5.5 17 IS 111/104 NN 1:1 SG 527:184 100-cP SO 25 — — 150/24 76±1 9 5.5 12 IS 112/102 OO 3:1 SG 527:184 100-cP SO 25 — — 150/24 46±2 6 3.7 8 IS 114/101 PP 3:1 SG 527:184 — — — — 150/24 50±2 10 4 49 IS 123/100 QQ 1:3 SG 527:184 — — — — 150/24 104±5 141 130 154 NS 122/95 RR 1:1 SG 527:184 — — — — 150/24 110±5 19 6.7 37 IS 117/88 SS 9:1 SG 527:184 100-cP SO 25 — — 150/24 8.0±0.8 6 4.1 7 IS 121/98 TT 9:1 SG 527:184 — — — — 150/24 9.1±0.9 134 132 139 NS 121/96 UU PFPE — — — — UVA 5 min 160±35 238 200 281 NS 115/93 VV PFPE Krytox 100 25 — — UVA 5 min 96±24 31 17 53 IS 115/95 WW PFPE Krytox 105 25 — — UVA 5 min 124±33 31 16 55 IS 104/98 XX PFPE Krytox 103 25 — — UVA 5 min — 12 10 13 IS 114/91 YY PFPE — — CN4002 10 UVA 5 min — 45 33 51 L 117/91 ZZ FPU — — — — 80/72 1098±98 538 257 627 NS 103/72 AB* FPU — — — — 80/72 475±14 394 334 479 NS 105/73 AC* FPU — — — — 80/72 316±17 284 204 399 NS 101/73 AD* FPU Krytox 100 25 — — 80/72 1142±158 595 538 713 IS 101/72 AE* FPU Krytox 105 25 — — 80/72 1112±77 392 283 520 IS 105/72 AF* FPU — — NCO C50 75 150/24 1332±48 246 194 320 IS 108/84 AG* FPU 100-cP SO 5 NCO C50 75 80/72 82 61 100 IS 109/82 AH* FPU 100-cP SO 10 NCO C50 75 80/72 49 22 66 IS 106/96 AI PS — — — — RT/24 447,000‡ 336 189 370 NS 97/86 AJ PS 200 Mw PS 25 — — RT/24 — 424 271 569 IS 103/74 AK PS 200 Mw PS 50 — — RT/24 — 570 378 642 IS 109/58 AL PS 540 Mw PS 25 — — RT/24 — 477 454 510 IS 100/79 AM PS SO AP 1000 25 — — RT/24 — 92 59 112 L 103/97 AN PS PMPS 10 — — RT/24 — 354 218 491 IS 98/84 AO PS PMPS 5 — — RT/24 — 333 217 498 IS 99/84 AP PIB — — — — RT/24 8,000‡ 395 335 453 NS 125/56 AQ PIB Polybutene 25 — — RT/24 — 288 220 419 IS 128/56 AR PIB Polybutene 50 — — RT/24 — 459 341 620 IS 130/17 AT PIB Polybutene 75 — — RT/24 — 268 176 442 IS 128/72 AU VytaFlex10 — — — — RT/24 26±7 144 84 254 NS 52/12 AV VytaFlex40 — — — — RT/24 95±14 151 118 192 NS 80/26 AW VytaFlex60 — — — — RT/24 290±17 261 157 360 NS 82/23 AX† VytaFlex40 Vegetable 20 — — RT/24 53±4 10.5 4.6 22 L 68/21 AY* VytaFlex40 Cod liver 15 — — RT/24 29±2 27 9 51 IS 75/12 AZ* VytaFlex40 100-cP SO 10 RT/24 — 41 18 83 L 82/45 BA VytaFlex40 — — NCO Di-50 1 RT/24 47±3 109 51 179 IS 96/49 BB VytaFlex40 — — NCO Di-50 5 RT/24 52±2 101 42 232 IS 110/56 BC VytaFlex40 — — NCO Di-50 10 RT/24 34±7 139 49 243 IS 113/60 BD* VytaFlex40 100-cP SO 10 NCO Di-100 50 RT/24 21±1 11 6 15 IS 97/89 BE* VytaFlex40 — — NCO C50 50 RT/24 42±0.4 44 25 55 IS 106/81 BE† VytaFlex40 100-cP SO 5 NCO C50 50 RT/24 36 18 57 IS 100/85 BF* VytaFlex40 100-cP SO 10 NCO C50 50 80/72 11 6 17 IS 95/86 BG* VytaFlex40 — — NCO C50 75 RT/24 171±4 49 38 65 IS 102/85 BH* VytaFlex40 100-cP SO 10 NCO C50 75 RT/24 9 3 12 IS 91/82 BI* VytaFlex40 1000-cP SO 10 NCO C50 75 RT/24 10 5 14 IS 99/90 BJ* VytaFlex40 5-cP SO 10 NCO C50 75 RT/24 18 12 24 IS 102/83 BK VytaFlex40 10,000-cP SO 10 NCO C50 75 RT/24 19 14 31 IS 102/92 BL VytaFlex40 100-cP SO 5 — — RT/24 — 77 70 90 L 70/42 BM VytaFlex40 100-cP SO 10 — — RT/24 — 80 58 91 L 68/42 BN VytaFlex40 100-cP SO 15 — — RT/24 — 98 68 128 L 65/41 BO VytaFlex40 100-cP SO 20 — — RT/24 — 93 76 107 L 67/42 BO VytaFlex40 Vegetable 5 — — RT/24 62±2 128 77 200 IS 79/23 BQ VytaFlex40 Vegetable 10 — — RT/24 62±4 238 233 247 IS 89/48 BR VytaFlex40 Vegetable 15 — — RT/24 49±2 121 91 151 IS 32/20 BS VytaFlex40 Vegetable 20 — — RT/24 53±4 173 141 227 IS 43/34 BT VytaFlex40 Cod liver 5 — — RT/24 — 129 107 166 IS 67/29 BU VytaFlex40 Cod liver 10 — — RT/24 — 70 56 85 IS 59/34 BV VytaFlex40 Cod liver 15 — — RT/24 — 110 100 120 IS 46/34 BW† VytaFlex40 Cod liver 15 — — RT/24 29±2 4 2 9 IS 43/25 BX† VytaFlex40 Vegetable 15 — — RT/24 52±1 11 3 15 IS 88/44 BY† VytaFlex40 Safflower 2.5 — — RT/24 63±0.5 30 20 43 IS 100/32 BZ* VytaFlex40 Safflower 5 — — RT/24 50±0.5 11 9 16 IS 82/28 BA* VytaFlex40 Safflower 10 — — RT/24 45±5 6 4 12 IS 72/24 CB† VytaFlex40 Safflower 15 — — RT/24 33±1 4 1 7 IS 67/29 CC† VytaFlex40 Safflower 20 — — RT/24 32±0.4 6 3 11 L 56/44 CD† VytaFlex40 Safflower 25 — — RT/24 45±2 4 2 6 L 52/43 CE VytaFlex40 Cod liver 20 — — RT/24 — 97 76 114 L 34/21 *Films that were spray-coated (500 mg/ml). All others are spin-cast at 1500 rpm for 60 s (200 mg/ml).
†Films that were dip-coated (500 mg/ml).
‡Approximated from the elastic modulus of the polymer.
Supplementary Materials
Supplementary material for this article is available at http://advances.sciencemag.org/cgi/content/full/2/3/e1501496/DC1
Text
Fig. S1. Liquid layer surface degradation.
Fig. S2. Surface chemistry independence.
Fig. S3. Tensile test data.
Fig. S4. Interfacial slippage mechanism additional data.
Fig. S5. Icephobicity of coated meshes.
Fig. S6. Elastomer solubility parameter determination.
Movie S1. Ice releasing from its own weight.
Movie S2. Mechanical strength of icephobic PU.
Additional Files
Supplementary Materials
This PDF file includes:
- Text
- Fig. S1. Liquid layer surface degradation.
- Fig. S2. Surface chemistry independence.
- Fig. S3. Tensile test data.
- Fig. S4. Interfacial slippage mechanism additional data.
- Fig. S5. Icephobicity of coated meshes.
- Fig. S6. Elastomer solubility parameter determination.
- Legends for movies S1 and S2
Other Supplementary Material for this manuscript includes the following:
Files in this Data Supplement:
