Fluoro-Decyl POSS (FDP) has shown strong potential as a water repellant surface coating. Additionally, Fomblin is a solvent believed to have the ability to control the crystallization of POSS compounds on surfaces. Controlling the crystallization is key to improving water repelling abilities of surfaces. Thus, dip coating FDP and Fomblin onto surfaces is being investigated for water repulsion, mechanical stability, and deposition feasibility. Relative water repelling abilities of different coatings were determined by measuring contact angle of surfaces with water. Coatings with and without POSS and Fomblin were compared. It was shown that the surfaces treated with both POSS and Fomblin were better at repelling water than those with just POSS or Fomblin alone, or neither

Alston, Jeffrey

Guenthner, Andrew

Kirby, Shawn PJ

English

Fluoro-Decyl POSS (FDP) has shown strong potential as a water repellant surface coating. Additionally, Fomblin is a solvent believed to have the ability to control the crystallization of POSS compounds on surfaces. Controlling the crystallization is key to improving water repelling abilities of surfaces. Thus, dip coating FDP and Fomblin onto surfaces is being investigated for water repulsion, mechanical stability, and deposition feasibility. First, temperature dependence of solubility of Fluoro-Decyl POSS in Fomblin was tested using Dynamic Light Scattering. Relative water repelling abilities of different coatings were determined by measuring contact angle of surfaces with water. Coatings with and without POSS and Fomblin were compared. It was shown that the surfaces treated with both POSS and Fomblin were better at repelling water than those with just POSS or Fomblin alone, or neither

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1Usage of Fomblin Y to Improve Water Repellence of Surface CoatingsShawn Kirby, Jeffrey Alston,Andrew GuenthnerDistribution A: Approved for Public Release. Distribution Unlimited.2Background• Hydrophobic coatings have a multitude of potential uses, from repelling ice and removing chemical agents• Fluoro Decyl Poss (FDP) is under testing for use as a hydrophobic coating additive to PMMA• POSS stands for Polyhedral oligomeric silsesquioxaneDistribution A: Approved for Public Release. Distribution Unlimited.3Background• Fluoro Decyl POSS is extremely hydrophobic because of it’s high amount of fluorination• Even if the surface is made of a hydrophobic material, but it is rough, it may take a high amount of energy to remove the water droplets from the surfaceDistribution A: Approved for Public Release. Distribution Unlimited.4BackgroundDistribution A: Approved for Public Release. Distribution Unlimited.5Background• PMMA stands for Poly(methyl methacrylate), which is more commonly known commercially as plexiglass Distribution A: Approved for Public Release. Distribution Unlimited.6Background• Fomblin Y is a solvent that impedes FDP from crystalizingDistribution A: Approved for Public Release. Distribution Unlimited.7Objective• Our goal was to test the feasibility of using FomblinY to reduce the crystal formation of the PMMA-FDP mixture. Theoretically, reducing crystal structure could decrease the energy needed to remove a dropOld Mixture New MixtureAK225PMMAPOSSAK225PMMAPOSSFomblin YDistribution A: Approved for Public Release. Distribution Unlimited.8Procedures• First, Dynamic Light Scattering (DLS) was used to determine the solubility of POSS in Fomblin YDistribution A: Approved for Public Release. Distribution Unlimited.9Procedures• A coating solution was developed with the desired components for comparison.Solution: A B C DContents: 80% AK225 10% PMMA10% FDP78% AK225 9% PMMA9% FDP4% Fomblin Y67.5% AK225 27.5% PMMA5% Fomblin Y70% AK225 30% PMMADistribution A: Approved for Public Release. Distribution Unlimited.10Procedures • Silicon Wafers were dip coated into the solutions. Three wafers were dipped in each solution.Distribution A: Approved for Public Release. Distribution Unlimited.11Contact Angle• The more attracted the water is to the surface, the lower the contact angle• The more repelled, the higher the contact angleDistribution A: Approved for Public Release. Distribution Unlimited.12Procedure• Contact angle measurements were taken to measure the relative hydrophobicity of the surfacesDistribution A: Approved for Public Release. Distribution Unlimited.13Procedure• Contact Angle Measurements were taken to measure the relative hydrophobicity of the surfacesDistribution A: Approved for Public Release. Distribution Unlimited.14Data and Observations• Unannealed samples• The surfaces treated with FDP and Fomblin Y had the highest contact angleSolution: A B C DContents: 80% AK225 10% PMMA10% FDP78% AK225 9% PMMA9% FDP4% Fomblin67.5% AK225 27.5% PMMA5% Fomblin70% AK225 30% PMMAAverage Advancing Contact Angle:74.9⁰ 88.0⁰ 70.0⁰ 70.1⁰Distribution A: Approved for Public Release. Distribution Unlimited.15Procedure• Most of the wafers, (two of each solution) were annealed in an oven at 100⁰C for 24 hours to investigate the effects of boiling off the Fomblin. Distribution A: Approved for Public Release. Distribution Unlimited.16Procedure• We wanted to attempt to remove the Fomblin• Fomblin has an extremely low vapor pressure. Thus, the samples were heated in an oven at 100 degrees Celsius overnight in an attempt to remove the Fomblin• If we increased the temperature too much, we would have caused the FDP to sublime• Thus, we needed to use a relatively low temperature at standard pressure for an extended period of timeDistribution A: Approved for Public Release. Distribution Unlimited.17Data and Observations• Annealed samples at 100⁰C• Annealing improved the hydrophobicity and stability of all surfacesSolution: A B C DContents: 80% AK225 10% PMMA10% FDP78% AK225 9% PMMA9% FDP4% Fomblin Y67.5% AK225 27.5% PMMA5% Fomblin Y70% AK225 30% PMMAAverage Advancing Contact Angle:93.9⁰ 96.7⁰ 79.0⁰ 80.5⁰Distribution A: Approved for Public Release. Distribution Unlimited.18Data and Observations• What would further heating do?• Further remove solvents, improving the surface?• Or damage the surface?Distribution A: Approved for Public Release. Distribution Unlimited.19Data and ObservationsSolution: A B C DContents: 80% AK225 10% PMMA10% FDP78% AK225 9% PMMA9% FDP4% Fomblin67.5% AK225 27.5% PMMA5% Fomblin70% AK225 30% PMMAAverage Advancing Contact Angle:92.9⁰ 93.8⁰ 75.0⁰ 80.2⁰• Annealed at 180⁰C• May have caused some slight damage to the coatingsDistribution A: Approved for Public Release. Distribution Unlimited.20Conclusions• Again, the surfaces treated with FDP and FomblinYhad the highest contact angle• Additionally, the annealed samples were more stable when exposed to water, which indicates that the Fomblin was removed at 100 Celsius. The FDP was not removed at this temperature. Distribution A: Approved for Public Release. Distribution Unlimited.21Further Work• Further work will need to be done to ensure that the PMMA and FDP are indeed forming a smooth surface. SEM and EDX would be examples of experiments to run to confirm this.• Additionally, the surface coatings can be improved by dip coating in a clean room. This would minimize dust and other impurities landing in the solution or on the silicon wafers• Additionally, spin coating provides a higher quality sample for future research• Need to figure out why advancing contact angles were not 120 degreesDistribution A: Approved for Public Release. Distribution Unlimited.22• Special thanks to:• Jeffrey Alston• Andrew Guenthner• Patrick Rice• Yvonne Campos• CSU STAR ProgramDistribution A: Approved for Public Release. Distribution Unlimited.23Questions?Distribution A: Approved for Public Release. Distribution Unlimited.

Usage of Fomblin Y to Improve Water Repellence of Surface Coatings

Usage of Fomblin Y to Improve Water Repellence of Surface CoatingsShawn Kirby1, Jeffrey Alston2, Andrew Guenthner3• Fluoro Decyl POSS (FDP) has a high potential for applications in preventing both ice build up and chemical contamination. This is because FDP is water repellant. This is due to it’s high amount of fluorination. Theoretically, adding FDP to coatings can be further improved by reducing the amount of crystal structure and making them more amorphous.Can adding Fomblin Y to FDP solutions used for dip coating decrease crystallinity and thus increase hydrophobicity?Step 1•Four test solutions were made to test the effects of adding Fomblin Y and FDP to PMMA (plexiglass) coatings.Step 2•Silicon wafers were dip coated into the solutions.Step 3•One set of samples was annealed at 100⁰C, another at 180⁰C, a final set was left unannealed.Step 4Contact angle measurements were taken to determine relative hydrophobicity of the different surfaces.• Adding Fomblin Y to dip coating solutions increased the contact angle of water on the samples, thus it increased the water repellence.• Heating the samples in an oven for 24 hours at 100⁰ C made the coatings more stable. The unannealed samples had their coatings “washed off” by the water during contact angle measurements.• However, heating them for 24 hours at 180⁰ C appears to have slightly degraded the coating, decreasing water repellence and contact angle.• Future work will focus on determining the surface structure using SEM and other techniques, as well as testing other coating methods.Figure 1: The blue regions represent “canyons” in the crystalline surface that water can fall into, making it harder to remove.Figure 3: Fomblin Y has a very low vapor pressure and does not evaporate easily. FDP is also very soluble in Fomblin, due to them both having high amount of fluorination. Solution: A B C DContents: 80% AK225 10% PMMA10% FDP78% AK225 9% PMMA9% FDP4% Fomblin Y67.5% AK225 27.5% PMMA5% FomblinY70% AK225 30% PMMAUnannealed 74.9⁰ 88.0⁰ 70.0⁰ 70.1⁰Annealed at 100⁰C 93.9⁰ 96.7⁰ 79.0⁰ 80.5⁰Annealed at 180⁰C 92.9⁰ 93.8⁰ 75.0⁰ 80.2⁰1: California State University, Long Beach 2: ERC Incorporated 3: Air Force Research Laboratory, Propulsion DirectorateContact AngleFigure 4: The higher the contact angle, the more repellant the surface is of the water. This is similar to water “beading up” on a freshly waxed car.Figure 2: Fluoro Decyl POSS is a silicon oxide cage with a long, fluorinated carbon chains on each silicon atom, for eight total.Conclusions and Future WorkBackground Procedure ResultsQuestionCoating Components TestedProgram SponsorsThe 2017 STEM Teacher and Researcher Program and this project have been made possible through support from Chevron (www.chevron.com), the National Marine Sanctuary Foundation (www.marinesanctuary.org), the California State University Office of the Chancellor, and California Polytechnic State University, in partnership with the Air Force Research Laboratory, Aerospace Systems Directorate, and the Air Force Office of Scientific ResearchTable 1: Contact angles of different samples in comparison to coating solution contents and annealing.Distribution A: Approved for Public Release. Distribution Unlimited.

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Usage of Fomblin Y to Improve Water Repellence of Surface Coatings

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