Hydrogen-Bonding Surfaces for Ice Mitigation: The Effect of Surface Chemical Functionality Upon Ice

Adhesion Joseph Smith 1, Christopher Wohl 1, Jereme Doss2, Destiny Spence3,

Richard Kreeger4, Jose Palacios5, Taylor Knuth5, Kevin Hadley6, and Nicholas McDougal6

1NASA Langley Research Center, Hampton, VA 23681, USA 2National Institute of Aerospace, Hampton, VA 23666, USA

3NASA USRP Researcher, NASA Langley Research Center, Hampton, VA 23681, USA 4 NASA Glenn Research Center, Cleveland, OH 44135, USA

5The Pennsylvania State University, University Park, PA 16802, USA 6South Dakota School of Mines and Technology, Rapid City, SD 57701, USA

NARI  2015  Seedling  Technical  Virtual  Seminar,  March  18-­‐19,  2015       1  

Background

NARI  2015  Seedling  Technical  Virtual  Seminar,  March  18-­‐19,  2015       2  

❄  Icing ­  Ground problem during cold months

•  Freezing drizzle/rain ­  In-flight problem year round

•  Results from super-cooled water droplets impacting the aircraft surface while flying through a cloud

•  Most occurrences are between 0 and -20°C

❄  Icing types encountered in-flight ­  Glaze/Clear, Rime, Mixed ­  Dependent upon

•  Air temperature (0 to -20°C) •  Liquid water content (0.3-0.6 g/m3) •  Droplet size (median volumetric diameter of 15-40 µm)

M.K. Politovich, “Aircraft Icing” in Encyclopedia of Atmospheric Sciences, Academic Press, Oxford, 2003, 68-75. H.E Addy Jr., M.G. Potapczuk, and D.W. Sheldon, “Modern Airfoil Ice Accretions,” NASA TM 107423, 1997.

Background

NARI  2015  Seedling  Technical  Virtual  Seminar,  March  18-­‐19,  2015       3  

M.K. Politovich, “Aircraft Icing” in Encyclopedia of Atmospheric Sciences, Academic Press, Oxford, 2003, 68-75. H.E Addy Jr., M.G. Potapczuk, and D.W. Sheldon, “Modern Airfoil Ice Accretions,” NASA TM 107423, 1997.

Glaze/Clear   Rime   Mixed  

•  Small droplets •  Brittle and opaque, milky

appearance •  Rapid freezing after droplet

impact with growth into the airstream

•  Easier to remove than glaze

•  Variable droplet size •  Combination of glaze

and rime ice

•  Large droplets •  Clear, nearly transparent,

smooth, waxy thus hard to see •  Gradual freezing after droplet

impact can result in runback along surface generating raised edges (i.e. horns)

•  Difficult to remove

Background

NARI  2015  Seedling  Technical  Virtual  Seminar,  March  18-­‐19,  2015       4  

❄  Current alleviation strategies ­  Pneumatic boots ­  Heated surfaces ­  De-icing fluids (i.e., ethylene- and propylene-based glycols)

❄  A passive approach mitigating ice adhesion during the entire aircraft flight profile is desirable.

­  Superhydrophobic surfaces1

­  Surfaces containing anti-freeze proteins2

­  Slippery liquid-infused porous surfaces3

­  Aqueous lubricating layer4

1. S.A. Kulinich et. al., Langmuir, 27 (2011) 25-29. 2. Anitei, S. Fish 'Antifreeze' Against Icy Aeroplanes. Aug. 8, 2007; http://news.softpedia.com/news/Fish-Antifreeze-Against-Icy-Aeroplanes-62189.shtml 3. L. Mishchenko, et. al.,”Design of Ice-free Nanostructured Surfaces Based on Repulsion of Impacting Water Droplets,” ACS Nano, 4 (2010) 7699-7707. 4. R. Dou et.al., “Anti-icing Coating with an Aqueous Lubricating Layer,” ACS Appl. Mater. Interfaces (2014).

Objective

NARI  2015  Seedling  Technical  Virtual  Seminar,  March  18-­‐19,  2015       5  

Investigate coated surfaces having controlled chemical functionality and carbon chain length between the substrate surface and the chemical functionality. ❄  Prepare and characterize substituted alkyldimethylalkoxysilanes containing Hydrogen Bonding (HB) and non-HB groups.

­  ATR-FTIR, NMR (1H, 13C, 29Si) ❄  Prepare and characterize aluminum (Al) substrates coated with pure and mixtures of alkyldimethylalkoxysilanes containing HB and non-HB groups.

­  Contact Angle Goniometry ❄  Determine IASS of coated Al substrates in a simulated environment with comparison to uncoated Al.

­  Adverse Environment Rotor Test Stand

To assess the effect of surface chemical functionalization upon ice adhesion shear strength (IASS).

Approach

Substituted Dimethylalkoxysilanes

NARI  2015  Seedling  Technical  Virtual  Seminar,  March  18-­‐19,  2015       6  

Si

CH3

CH3

O CH2 CH3xH3CH2C

x = 2 (C3A), 6 (C7A), 10 (C11A)

Si

CH3

CH3

O CH2 ORy

H3CH2C

X = -, y = 7 (C7H), 10 (C10H), 11 (C11H)

R = -CH2CH2OCH3, y = 5

X = -OCH2CH2-, y = 2 (EG)

C5MEG

EG

Non-hydrogen bonding

Hydrogen-bonding (donor/acceptor)Hydroxyl

Hydrogen-bonding (acceptor)

Aliphatic

Si

CH3

CH3

O CH2 Xy

Coating Al Substrate I

NARI  2015  Seedling  Technical  Virtual  Seminar,  March  18-­‐19,  2015       7  

Si

CH3

CH3

O CH2 CH3xH3CH2C

x = 2 (C3A), 6 (C7A), 10 (C11A)

R = -CH2CH2OCH3, y = 5C5MEG

HOAc, EtOH, H2O

Hydrogen-bonding (acceptor)

Aliphatic

Si

CH3

CH3

O CH2 ORy

H3CH2CSame method for

Non-hydrogen bonding

CH2Cl2, RTSi

CH3

CH3

HO CH2 CH3x

Si

CH3

CH3

HO CH2 CH3xAl

OH + Si

CH3

CH3

CH2 CH3xAl

O

HOAc, EtOH, H2O

CH2Cl2, RTSi

CH3

CH3

HO CH2 Xy

AlOH + Si

CH3

CH3

CH2 Xy

AlO

Si

CH3

CH3

O CH2 Xy

X = -, y = 7 (C7H), 10 (C10H), 11 (C11H) X = -OCH2CH2-, y = 2 (EG)EG

Hydrogen-bonding (donor/acceptor)Hydroxyl

OH

Si

CH3

CH3

HO CH2 Xy

OH OH

Coating Al Substrate II

NARI  2015  Seedling  Technical  Virtual  Seminar,  March  18-­‐19,  2015       8  

Receding Water Contact Angle

NARI  2015  Seedling  Technical  Virtual  Seminar,  March  18-­‐19,  2015       9  

0

20

40

60

80

100

120

C3A C7A

C11A

C7A (5

0%)/C

3A (5

0%)

C11A (2

5%)/C

3A(75

%)

C11A (5

0%)/C

3A (5

0%)

C11A (7

5%)/C

3A (2

5%)

C11A (5

0%)/C

7A (5

0%)

C7H

C10H

C11H

EG

C7H (5

0%)/C

3A (5

0%)

C7H (5

0%)/C

7A (5

0%)

C10H (5

0%)/C

7A (5

0%)

EG (50%

)/C3A

(50%

)

EG (25%

)/ C3A

(75%

)

C5MEG

C5MEG (5

0%) /C

3A (5

0%)

C5MEG (5

0%)/C

7A (5

0%)

C5MEG (5

0%)/C

7H(50

%)

Wat

er R

eced

ing

Con

tact

Ang

le, °

Al Control

Higher Ice

Adhesion Strength

Lower Ice

Adhesion Strength

x = 2 (C3A), 6 (C7A), 10 (C11A)Si

CH3

CH3

CH2 CH3xAl

O

X = -, y = 7 (C7H), 10 (C10H), 11 (C11H)

X = -OCH2CH2-, y = 2EGSi

CH3

CH3

CH2 Xx

AlO OH

C5MEGSi

CH3

CH3

CH2 OCH2CH2OCH3 5Al

O

x = 2 (C3A), 6 (C7A), 10 (C11A)

X = --, y = 7 (C7H), 10 (C10H), 11 (C11H)

X = -OCH2CH2-, y = 2 (EG)

C5MEG

Adverse Environment Rotor Test Stand  

NARI  2015  Seedling  Technical  Virtual  Seminar,  March  18-­‐19,  2015       10  

❄  Pennsylvania State University ❄  Testing performed under simulated icing conditions.

­  Super-cooled water injected into test chamber.

­  Tests conducted from -8 to -16°C; commenced at -16°C

­  Icing cloud density (i.e. liquid water content) of 1.9 g/m3

­  Water droplet mean volumetric diameter of 20 µm

❄  Ice accumulation and subsequent shedding enabled determination of Ice Adhesion Shear Strength after data analysis and visual assessment. ❄  Experimental details discussed in J. Soltis, J. Palacious T. Eden, and D. Wolfe, “Evaluation of Ice Adhesion Strength on Erosion Resistant Materials,” 54th AIAA/ ASME/ASCE/AHS/ASC Structures, Structural Dynamics, and Materials Conference, April 8-11, 2013, Boston, MA, AIAA 2013-1509.

Credit: The Pennsylvania State University

NARI  2015  Seedling  Technical  Virtual  Seminar,  March  18-­‐19,  2015       11  

One Component Coatings  

0"

50"

100"

150"

200"

250"

Al"Control" C3A" C7A" C11A"

Ice$Ad

hesion

$She

ar$Str.,$kPa$

/8°C" /12°C" /16°C"

Non-HB: Chain Length Effect

NARI  2015  Seedling  Technical  Virtual  Seminar,  March  18-­‐19,  2015       12  

x = 2 (C3A), 6 (C7A), 10 (C11A)Si

CH3

CH3

CH2 CH3xAl

O

0"

20"

40"

60"

80"

100"

120"

140"

160"

180"

200"

Al"Control" C7H" C10H" C11H" EG"

Ice$Ad

hesion

$She

ar$$Str.,$kPa$

38°C" 312°C" 316°C"

Si

CH3

CH3

CH2 Xy

AlO

X = --, y = 7 (C7H), 10 (C10H), 11 (C11H)

X = -OCH2CH2-, y = 2 (EG)

OH

HB (donor/acceptor): Chain Length Effect

NARI  2015  Seedling  Technical  Virtual  Seminar,  March  18-­‐19,  2015       13  

0"

20"

40"

60"

80"

100"

120"

140"

160"

180"

200"

Al"Control" C5MEG"

Ice$Ad

hesion

$She

ar$Str.,$kPa$

38°C" 312°C" 316°C"

HB (acceptor)

NARI  2015  Seedling  Technical  Virtual  Seminar,  March  18-­‐19,  2015       14  

C5MEGSi

CH3

CH3

CH2 OCH2CH2OCH3 5Al

O

Functional Group and Chain Length

NARI  2015  Seedling  Technical  Virtual  Seminar,  March  18-­‐19,  2015       15  

0"

50"

100"

150"

200"

250"

C7A" C7H" C11A" C11H"

Ice$Ad

hesion

$She

ar$Str.,$kPa$

*8°C" *12°C" *16°C"

Si

CH3

CH3

CH2 CH3xAl

O x = 6 (C7A), 10 (C11A)

X = --, y = 7 (C7H), 11 (C11H) Si

CH3

CH3

CH2 Xy

AlO OH

Functional Group: Similar Chain Length

NARI  2015  Seedling  Technical  Virtual  Seminar,  March  18-­‐19,  2015       16  

C5MEGSi

CH3

CH3

CH2 OCH2CH2OCH3 5Al

O

Si

CH3

CH3

CH2 CH3xAl

O

X = --, y = 10 (C10H), 11 (C11H) Si

CH3

CH3

CH2 Xy

AlO OH

x = 6 (C7A)

C5MEG

0"

50"

100"

150"

200"

250"

Al"Control" C11A" C10H" C11H" C5MEG"

Ice$Ad

hesion

$She

ar$Str.,$kPa$

18°C" 112°C" 116°C"

One Component Coating Summary

NARI  2015  Seedling  Technical  Virtual  Seminar,  March  18-­‐19,  2015       17  

❄  Aliphatic (non-HB) ­  Minimum chain length (C7A) needed to decrease interaction of

ice with the substrate (C3A) ­  Long chain length (C11A) resulted in coating degradation ­  Performance compared to HB series dependent on chain length

x = 2 (C3A), 6 (C7A), 10 (C11A)Si

CH3

CH3

CH2 CH3xAl

O

X = -, y = 7 (C7H), 10 (C10H), 11 (C11H)

X = -OCH2CH2-, y = 2EGSi

CH3

CH3

CH2 Xx

AlO OH

❄  Hydroxy1 and EG (HB donor/acceptor) ­  Not much difference in IASS between test temperatures ­  Long chain (C10H, C11H) performed better ­  EG performance similar to C7H

❄  C5MEG (HB acceptor) ­  Functional group performance similar to C7A ­  Comparable chain length performance

•  HB donor/acceptor (C10H, C11H) resulted in lower IASS •  C11A (non-HB) degraded

­  In general, performed better than EG

C5MEGSi

CH3

CH3

CH2 OCH2CH2OCH3 5Al

O

x = 2 (C3A), 6 (C7A), 10 (C11A)

X = --, y = 7 (C7H), 10 (C10H), 11 (C11H)

X = -OCH2CH2-, y = 2 (EG)

C5MEG

NARI  2015  Seedling  Technical  Virtual  Seminar,  March  18-­‐19,  2015       18  

Two Component Coatings  

Non-HB: Different Chain Lengths

NARI  2015  Seedling  Technical  Virtual  Seminar,  March  18-­‐19,  2015       19  

0"20"40"60"80"100"120"140"160"180"200"

Al"Control" 0" 50" 100"

Ice$Ad

hesion

$She

ar$Str.,$kPa$

C7A$in$C3A/C7A$coa8ngs,$%$

08°C" 012°C" 016°C" Si

CH3

CH3

CH2 CH3xAl

O x = 2 (C3A), 6 (C7A)

Increasing HB Content: Different Chain Lengths

NARI  2015  Seedling  Technical  Virtual  Seminar,  March  18-­‐19,  2015       20  

Si

CH3

CH3

CH2 CH3xAl

O x = 2(C3A)

X = --, y = 7 (C7H) Si

CH3

CH3

CH2 Xy

AlO OH

0"

20"

40"

60"

80"

100"

120"

140"

160"

180"

200"

Al"Control" 0" 50" 100"

Ice$Ad

hesion

$She

ar$$Str.,$kPa$

C7H$in$C3A/C7H$coa9ngs,$%$

08°C" 012°C" 016°C"

Increasing HB Content: Similar Chain Lengths

NARI  2015  Seedling  Technical  Virtual  Seminar,  March  18-­‐19,  2015       21  

0"

20"

40"

60"

80"

100"

120"

140"

160"

180"

200"

Al"Control" 0" 50" 100"

Ice$Ad

hesion

$She

ar$Str.,$kPa$

C7H$in$C7A/C7H$coa8ngs,$%$

08°C" 012°C" 016°C" Si

CH3

CH3

CH2 CH3xAl

O x = 6(C7A)

X = --, y = 7 (C7H) Si

CH3

CH3

CH2 Xy

AlO OH

0"20"40"60"80"100"120"140"160"180"200"

Al"Control" 0" 50" 100"

Ice$Ad

hesion

$She

ar$Str.,$kPa$

C10H$in$C7A/C10H$coa:ngs,$%$

08°C" 012°C" 016°C"

Increasing HB Content: Different Chain Lengths

NARI  2015  Seedling  Technical  Virtual  Seminar,  March  18-­‐19,  2015       22  

Si

CH3

CH3

CH2 CH3xAl

O x = 6(C7A)

X = --, y = 10 (C10H) Si

CH3

CH3

CH2 Xy

AlO OH

Increasing HB Content: Different Chain Lengths

NARI  2015  Seedling  Technical  Virtual  Seminar,  March  18-­‐19,  2015       23  

0"20"40"60"80"100"120"140"160"180"200"

Al"Control" 0" 25" 50" 100"

Ice$Ad

hesion

$She

ar$Str.,$kPa$

EG$in$EG/C3A$coa9ngs,$%$

08°C" 012°C" 016°C" Si

CH3

CH3

CH2 CH3xAl

O x = 2 (C3A)

X = -OCH2CH2-, y = 2 (EG) Si

CH3

CH3

CH2 Xy

AlO OH

Increasing HB (acceptor) Content: Different Chain Lengths

NARI  2015  Seedling  Technical  Virtual  Seminar,  March  18-­‐19,  2015       24  

0"20"40"60"80"100"120"140"160"180"200"

Al"Control" 0" 50" 100"

Ice$Ad

hesion

$She

ar$Str.,$kPa$

C5MEG$in$C3A/C5MEG$coa;ngs,$%$

08°C" 012°C" 016°C" Si

CH3

CH3

CH2 CH3xAl

O x = 2 (C3A)

C5MEGSi

CH3

CH3

CH2 OCH2CH2OCH3 5Al

O C5MEG

0"

20"

40"

60"

80"

100"

120"

140"

160"

180"

200"

Al"Control" 0" 50" 100"

Ice$Ad

hesion

$She

ar$Str.,$kPa$

C5MEG$in$C7A/C5MEG$coa;ngs,$%$

08°C" 012°C" 016°C"

NARI  2015  Seedling  Technical  Virtual  Seminar,  March  18-­‐19,  2015       25  

Increasing HB (acceptor) Content: Different Chain Lengths

Si

CH3

CH3

CH2 CH3xAl

O x = 6 (C7A)

C5MEGSi

CH3

CH3

CH2 OCH2CH2OCH3 5Al

O C5MEG

NARI  2015  Seedling  Technical  Virtual  Seminar,  March  18-­‐19,  2015       26  

Increasing HB (acceptor) Content: Different Chain Lengths

0"20"40"60"80"

100"120"140"160"180"200"

Al"Control" 0" 50" 100"

Ice$Ad

hesion

$She

ar$Str.,$kPa$

C5MEG$in$C7H/C5MEG$coa<ngs,$%$

08°C" 012°C" 016°C"

C5MEGSi

CH3

CH3

CH2 OCH2CH2OCH3 5Al

O

X = --, y = 7 (C7H) Si

CH3

CH3

CH2 Xy

AlO OH

C5MEG

Two Component Coating Summary

NARI  2015  Seedling  Technical  Virtual  Seminar,  March  18-­‐19,  2015       27  

❄  HB (donor/acceptor) and Aliphatic (non-HB) ­  General - Increasing HB component (Hydroxyl) increased

IASS •  Exception -16°C where IASS comparable •  C7A/C10H suggested degradation, base components

exhibited no degradation

­  EG/C3A •  25% EG inclusion exhibited comparable performance to

C3A •  50% EG inclusion

ª  Better performance than C3A at -8 and -12°C ª  Worse performance at -16°C

x = 2 (C3A), 6 (C7A), 10 (C11A)Si

CH3

CH3

CH2 CH3xAl

O ❄  Aliphatic (non-HB) ­  IASS increased with increasing short chain (C3A) component.

x = 2 (C3A), 6 (C7A)

X = -, y = 7 (C7H), 10 (C10H), 11 (C11H)

X = -OCH2CH2-, y = 2EGSi

CH3

CH3

CH2 Xx

AlO OH

x = 2 (C3A), 6 (C7A), 10 (C11A)Si

CH3

CH3

CH2 CH3xAl

O

X = --, y = 7 (C7H), 10 (C10H)

x = 2 (C3A), 6 (C7A)

X = -OCH2CH2-, y = 2 (EG)

NARI  2015  Seedling  Technical  Virtual  Seminar,  March  18-­‐19,  2015       28  

❄  HB (acceptor) and Aliphatic (non-HB) ­  Performance dependent upon non-HB chain length

•  C3A afforded lower IASS compared to C7A ª  Presumably due to better accessibility of

in-chain ether group to water •  C5MEG/C3A overall performance better than

EG/3A 50/50

C5MEGSi

CH3

CH3

CH2 OCH2CH2OCH3 5Al

O

x = 2 (C3A), 6 (C7A), 10 (C11A)Si

CH3

CH3

CH2 CH3xAl

O

❄  HB (acceptor) and HB (acceptor/donor) ­  In general - performance not as good as HB

(acceptor) alone ­  Data suggested coating degradation

C5MEGSi

CH3

CH3

CH2 OCH2CH2OCH3 5Al

O

X = -, y = 7 (C7H), 10 (C10H), 11 (C11H)

X = -OCH2CH2-, y = 2EGSi

CH3

CH3

CH2 Xx

AlO OH

Two Component Coating Summary

x = 2 (C3A), 6 (C7A)

X = --, y = 7 (C7H)

C5MEG

C5MEG

0

20

40

60

80

100

120

C3A C7A

C11A

C7A (5

0%)/C

3A (5

0%)

C11A (2

5%)/C

3A(75

%)

C11A (5

0%)/C

3A (5

0%)

C11A (7

5%)/C

3A (2

5%)

C11A (5

0%)/C

7A (5

0%)

C7H

C10H

C11H

EG

C7H (5

0%)/C

3A (5

0%)

C7H (5

0%)/C

7A (5

0%)

C10H (5

0%)/C

7A (5

0%)

EG (50%

)/C3A

(50%

)

EG (25%

)/ C3A

(75%

)

C5MEG

C5MEG (5

0%) /C

3A (5

0%)

C5MEG (5

0%)/C

7A (5

0%)

C5MEG (5

0%)/C

7H(50

%)

Wat

er R

eced

ing

Con

tact

Ang

le, °

Al Control

y y, except -16C n degraded

Higher Ice

Adhesion Strength

Lower Ice

Adhesion Strength

Receding Water Contact Angle

NARI  2015  Seedling  Technical  Virtual  Seminar,  March  18-­‐19,  2015       29  

x = 2 (C3A), 6 (C7A), 10 (C11A)Si

CH3

CH3

CH2 CH3xAl

O

X = -, y = 7 (C7H), 10 (C10H), 11 (C11H)

X = -OCH2CH2-, y = 2EGSi

CH3

CH3

CH2 Xx

AlO OH

C5MEGSi

CH3

CH3

CH2 OCH2CH2OCH3 5Al

O

x = 2 (C3A), 6 (C7A), 10 (C11A)

X = --, y = 7 (C7H), 10 (C10H), 11 (C11H)

X = -OCH2CH2-, y = 2 (EG)

C5MEG

Conclusions

NARI  2015  Seedling  Technical  Virtual  Seminar,  March  18-­‐19,  2015       30  

❄  Effect of coating composition on IASS is complex ­  One component coatings

•  Chain length effect upon IASS is functional group dependent •  No clear trend observed between functional groups

­  Two component coatings •  More relevant when incorporating functionalities into polymeric

systems •  General – increasing HB content (HB donor/acceptor) increased

IASS •  Mixed chain length effect upon IASS is composition/functional

group dependent

Future Work

NARI  2015  Seedling  Technical  Virtual  Seminar,  March  18-­‐19,  2015       31  

❄  Develop monomers with pendant groups based on non-HB and HB (acceptor) effects

❄  Prepare epoxies based on the developed monomers ❄  Test epoxy coated Al samples in AERTS to determine IASS

Acknowledgements ❄  Ronald Penner (Science Technology Corporation) ❄  Dennis Working (NASA)