Research ArticleSURFACE CHEMISTRY

Designing durable icephobic surfaces

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Science Advances  11 Mar 2016:
Vol. 2, no. 3, e1501496
DOI: 10.1126/sciadv.1501496
  • 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 Embedded Image = 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
    base
    Nonreactive
    oil
    wt %Reactive
    oil
    wt %Cure
    (°C/hour)
    ρCL
    (mol/m3)
    τice
    average (kPa)
    τice
    min.
    (kPa)
    τice
    max.
    (kPa)
    Typeθadvrec
    (°)
    ASG 184 10:1150/24307±8264245340NS120/94
    BSG 184 10:180/2333±45473657IS131/26
    CSG 184 20:180/2112±1178147251NS129/45
    DSG 184 4:180/233±458942165IS127/36
    ESG 184 3:180/2268±215629L122/76
    FSG 184 2:180/2222±914623L118/77
    GSG 184 5:280/2267±2116826L112/100
    HSG 184 1:180/2162±514629L112/89
    ISG 184 10:1100-cP SO2580/2219±13352656IS123/89
    JSG 184 10:1100-cP SO5080/272±118740120IS114/94
    KSG 184 10:1100-cP SO7580/2553071IS114/94
    LSG 184 10:1PMHS2580/2215±10101.031L105/103
    MSG 184 10:1PMHS5080/275±136731121IS118/101
    NSG 184 10:1PMHS7580/2174.939L121/102
    OSG 184 1:1100-cP SO2580/232±217358237IS124/86
    PSG 184 1:1100-cP SO5080/213±2461774IS124/82
    QSG 184 1:1100-cP SO7580/2180.1547IS104/103
    RSG 184 1:1PMHS2580/2102±5171.040L125/104
    SSG 184 1:1PMHS5080/214±460.730L106/105
    TSG 184 1:1PMHS7580/290.3531L105/103
    USG 184 10:1100-cP SO25PMHS25150/24536±97645078IS119/95
    VSG 184 10:1100-cP SO15PMHS1580/2311.0137L108/104
    WSG 184 10:1100-cP SO10PMHS10150/24459±97440116IS123/90
    XSG 184 10:1PMHS1080/2283±9374.071IS114/100
    YSG 184 10:1PMHS10150/24284±41173122234NS121/78
    ZSG 184 10:1PMHS2080/2197±4451982IS109/105
    AASG 184 10:1PMHS20150/24348±28643492IS118/93
    BBSG 184 10:1PMHS25150/24452±9302275346NS103/84
    CCSG 184 10:1100-cP SO25PMHS15150/24405±27584173IS112/104
    DDSG 184 10:1100-cP SO20PMHS2080/2107±2379.167IS109/100
    EESG 184 10:1100-cP SO25PMHS2580/2150±8355.177IS116/99
    FFSG 184 10:1100-cP SO25PMHS10150/24290±25412455IS112/108
    GGSG 184 10:15-cP SO2580/2181±5145109178IS121/90
    HHSG 184 10:11000-cP SO2580/2153±7453353IS100/85
    IISG 184 10:110000-cP SO2580/267±28113226L120/104
    JJSG 184 10:1SO AP 10002580/2216±36612171L113/78
    KKSG 527 1:1150/240.68147.625NS130/89
    LL1:9 SG 527:184100-cP SO25150/24182±11147.318IS112/103
    MM1:3 SG 527:184100-cP SO25150/24123±2105.517IS111/104
    NN1:1 SG 527:184100-cP SO25150/2476±195.512IS112/102
    OO3:1 SG 527:184100-cP SO25150/2446±263.78IS114/101
    PP3:1 SG 527:184150/2450±210449IS123/100
    QQ1:3 SG 527:184150/24104±5141130154NS122/95
    RR1:1 SG 527:184150/24110±5196.737IS117/88
    SS9:1 SG 527:184100-cP SO25150/248.0±0.864.17IS121/98
    TT9:1 SG 527:184150/249.1±0.9134132139NS121/96
    UUPFPEUVA 5 min160±35238200281NS115/93
    VVPFPEKrytox 10025UVA 5 min96±24311753IS115/95
    WWPFPEKrytox 10525UVA 5 min124±33311655IS104/98
    XXPFPEKrytox 10325UVA 5 min121013IS114/91
    YYPFPECN400210UVA 5 min453351L117/91
    ZZFPU80/721098±98538257627NS103/72
    AB*FPU80/72475±14394334479NS105/73
    AC*FPU80/72316±17284204399NS101/73
    AD*FPUKrytox 1002580/721142±158595538713IS101/72
    AE*FPUKrytox 1052580/721112±77392283520IS105/72
    AF*FPUNCO C5075150/241332±48246194320IS108/84
    AG*FPU100-cP SO5NCO C507580/728261100IS109/82
    AH*FPU100-cP SO10NCO C507580/72492266IS106/96
    AIPSRT/24447,000336189370NS97/86
    AJPS200 Mw PS25RT/24424271569IS103/74
    AKPS200 Mw PS50RT/24570378642IS109/58
    ALPS540 Mw PS25RT/24477454510IS100/79
    AMPSSO AP 100025RT/249259112L103/97
    ANPSPMPS10RT/24354218491IS98/84
    AOPSPMPS5RT/24333217498IS99/84
    APPIBRT/248,000395335453NS125/56
    AQPIBPolybutene25RT/24288220419IS128/56
    ARPIBPolybutene50RT/24459341620IS130/17
    ATPIBPolybutene75RT/24268176442IS128/72
    AUVytaFlex10RT/2426±714484254NS52/12
    AVVytaFlex40RT/2495±14151118192NS80/26
    AWVytaFlex60RT/24290±17261157360NS82/23
    AXVytaFlex40Vegetable20RT/2453±410.54.622L68/21
    AY*VytaFlex40Cod liver15RT/2429±227951IS75/12
    AZ*VytaFlex40100-cP SO10RT/24411883L82/45
    BAVytaFlex40NCO Di-501RT/2447±310951179IS96/49
    BBVytaFlex40NCO Di-505RT/2452±210142232IS110/56
    BCVytaFlex40NCO Di-5010RT/2434±713949243IS113/60
    BD*VytaFlex40100-cP SO10NCO Di-10050RT/2421±111615IS97/89
    BE*VytaFlex40NCO C5050RT/2442±0.4442555IS106/81
    BEVytaFlex40100-cP SO5NCO C5050RT/24361857IS100/85
    BF*VytaFlex40100-cP SO10NCO C505080/7211617IS95/86
    BG*VytaFlex40NCO C5075RT/24171±4493865IS102/85
    BH*VytaFlex40100-cP SO10NCO C5075RT/249312IS91/82
    BI*VytaFlex401000-cP SO10NCO C5075RT/2410514IS99/90
    BJ*VytaFlex405-cP SO10NCO C5075RT/24181224IS102/83
    BKVytaFlex4010,000-cP SO10NCO C5075RT/24191431IS102/92
    BLVytaFlex40100-cP SO5RT/24777090L70/42
    BMVytaFlex40100-cP SO10RT/24805891L68/42
    BNVytaFlex40100-cP SO15RT/249868128L65/41
    BOVytaFlex40100-cP SO20RT/249376107L67/42
    BOVytaFlex40Vegetable5RT/2462±212877200IS79/23
    BQVytaFlex40Vegetable10RT/2462±4238233247IS89/48
    BRVytaFlex40Vegetable15RT/2449±212191151IS32/20
    BSVytaFlex40Vegetable20RT/2453±4173141227IS43/34
    BTVytaFlex40Cod liver5RT/24129107166IS67/29
    BUVytaFlex40Cod liver10RT/24705685IS59/34
    BVVytaFlex40Cod liver15RT/24110100120IS46/34
    BWVytaFlex40Cod liver15RT/2429±2429IS43/25
    BXVytaFlex40Vegetable15RT/2452±111315IS88/44
    BYVytaFlex40Safflower2.5RT/2463±0.5302043IS100/32
    BZ*VytaFlex40Safflower5RT/2450±0.511916IS82/28
    BA*VytaFlex40Safflower10RT/2445±56412IS72/24
    CBVytaFlex40Safflower15RT/2433±1417IS67/29
    CCVytaFlex40Safflower20RT/2432±0.46311L56/44
    CDVytaFlex40Safflower25RT/2445±2426L52/43
    CEVytaFlex40Cod liver20RT/249776114L34/21

    *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.

    • 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

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      Other Supplementary Material for this manuscript includes the following:

      • Movie S1 (.mov format). Ice releasing from its own weight.
      • Movie S2 (.mov format). Mechanical strength of icephobic PU.

      Files in this Data Supplement:

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