Durability of Superhydrophobic Coatings - Sand Abrasion Test

TVE 16 064 juni Examensarbete 15 hp Juli 2016 Durability of Superhydrophobic Coatings - Sand Abrasion Test Hugo Harlin Max Holmberg Abstract Durability of Superhydrophobic Coatings - Sand Abrasion Test Hugo Harlin & Max Holmberg Teknisk- naturvetenskaplig fakultet UTH-enheten Besöksadress: Ångströmlaboratoriet Lägerhyddsvägen Hus 4, Plan Postadress: Box 536 751 21 Uppsala Telefon: 018 – 471 30 03 Telefax: 018 – 471 30 00 Hemsida: http://www.teknat.uu.se/student The interest in superhydrophobic coatings have increased exponentially in the recent decades due to their potential and versatility in their applications The use for superhydrophobic surfaces range from water repellent fabric, to self cleaning surfaces and numerous applications in industry In this project the durability of different superhydrophobic coatings have been examined The durability was tested by dropping sand on the surfaces from a set hight of 10 cm and a flow of 40 g/min The surfaces were mounted on a 45° angle The surfaces were abraded for 30 seconds at a time and the static, receding, and advancing contact angles along with the roll-of angle was measured Five of the surfaces were built up with nano particles and one was sand blasted and anodized to create a superhydrophobic structure The surfaces that withstood the most abrasion was the surface that had been calcined to improve adhesion and the surface that had been sand blasted and anodized Measurements showed that the roll-off angle and the receding contact angle were the two best indicators of the deterioration of a surface, while the static contact angle and the advancing contact angle varied little with abrasion The project was done at the company Technical Research Institute of Sweden (SP) at their chemistry, surfaces and materials department in Stockholm All coatings and equipment was supplied by SP Handledare: Mikko Tuominen & Mikael Järn Ämnesgranskare: Viviana Lopes Examinator: Martin Sjödin ISSN: 1401-5757, TVE 16 064 juni Contents Populă arvetenskaplig sammanfattning 2 Introduction 2.1 Basics of Superhydrophobicity 2 Materials and Methods 3.1 Materials 3.2 Sand abrasion test 4 4 Results Discussion Conclusions 10 1 Populă arvetenskaplig sammanfattning Ytor med vattenavstă otande egenskaper ă ar vanligt făorekommande i naturen Ta till exempel en vattenskră addare som kan st˚ a p˚ a en vattenyta med hjă alp av sina l anga vattenavstăotande ben I praktiken ¨ar vattenavst¨otande ytor v¨ aldigt anv¨ andbara med m˚ anga tillă ampningsomr aden Om husfasader och tak behandlas s a skulle vatten rulla av istă allet fă or att blă ota ytorna, vilket fă orhindrar tillvăaxten av măogel och văaxtlighet En smutsig vattenavstă otande yta kan enkelt rengă oras genom att den spolas av med vatten, smutsen plockas upp av vattendropparna som i sin tur rullar av ytan En vattenavstă otande yta m aste vara bestăandig mot slitage, och i detta projekt undersă oks slitt aligheten av olika hă ogpresterande vattenavstăotande ytor Slitaget bestod av sand som făoll mot ytan, vartefter en droppe placerades p˚ a ytan och dess form studerades Provet vinklades sedan och vinkeln d˚ a droppen rullar av, den s a kallade roll-off vinkeln, mă attes Roll-off vinkeln var den băasta indikatorn p a hur h allfasta ytorna var Fă or att tillverka en hă ogpresterande vattenavstă otande yta behăovs tv a faktorer; en ojăamn ytstruktur (p a văaldigt liten skala), och en vattenavstă otande ytkemi Fă or att en yta skall var slitt˚ alig m˚ aste ytstrukturen och ytkemin t˚ ala slitage Eftersom det finns flera metoder att skapa ytstrukturen samt applicera ytkemin, var projektet ett să att att jă amfă ora kombinationer av ytstrukturer och appliceringsmetoder făor att uppn a maximal h allbarhet Introduction The interest in superhydrophobic coatings have increased exponentially in the recent decades due to their potential and versatility in their applications The use for superhydrophobic surfaces range from water repellent fabric, to self cleaning surfaces and numerous applications in industry Surfaces with superhydrophobic properties are common in nature Take for example the legs of the water strider, which enables it to sit comfortably on the water’s surface due to their water repellency [1] Another example of a superhydrophobic surface is the leaves of the lotus plant Water droplets simply roll off the leaves, hindering the growth of harmful pathogens and the build up of dirt [2] Hydrophobic means water repellent, and is a very useful property since dirt, pollutants, chemicals, bacteria, and other unwanted substances are often water soluble and can easily be washed off a hydrophobic surface The ability to shed water efficiently means a surface stays clean and lessens the threat that contact with unwanted substances imply Superhydrophobic coatings can be used in many different applications, for example self-cleaning optical surfaces, energy conversion and conservation, environment-friendly self-cleaning underwater surfaces etc [3] The coatings that are examined in this report are intended to be used on heat sinks designed for heat pumps Hydrophobic coatings are widely applicable in industry, but for a coating to be viable it has to be durable enough for the given application In some cases this can be a demanding criteria to fulfil, and increasing the durability of hydrophobic coatings is thus of great interest 2.1 Basics of Superhydrophobicity The definition of a hydrophobic surface is a contact angle larger than 90 degrees A superhydrophobic surface is defined as having a contact angle larger than 150 degrees [4] The contact angle is defined as the angle between the liquid fluid interface and the tangent to the solid interface at the contact line between the three faces (see figure 1) [5] Measurements of static contact angles is not as simple as it may seem, on a non ideal surface a water droplet will have more than one stable contact angle (local energy minima) and thus it may be difficult to draw any conclusion just from the static contact angle measurement A better way of describing the contact angle is by measuring the Advancing Contact Angle (ADCA) and the Receding Contact Angle (RCA) As can be seen in figure ADCA is the highest contact angle for which there exists a local energy minimum and RCA is the lowest angle for which there exist a local energy minimum The ideal static CA will be between the RCA and the ADCA [5] Some hydrophobic surfaces may have a high contact angle but droplets will stick to the surface, this is in many cases an undesirable effect and can be measured with the role-off angle (RA) The role-off angle is the smallest angle between the sample surface and the horizontal plane, where a drop of water will roll off the surface No real surface is truly flat, and therefore one must consider the surface roughness when evaluating the hydrophobicity of a surface There are in general three different cases of how a droplet sits on top of a rough surface, the Wenzel state [6], the Cassie state, or a combination of the two [7] In the Wenzel state the droplet sits on top of the roughness and in the Cassie state the droplet is merged into the roughness of the surface (see figure 3).These states are called wetting states, and the Cassie state corresponds to a fully wetted droplet while the Wenzel state corresponds to a non wetted droplet In order to acquire a superhydrophobic surface there are two main properties a surface needs; Surface roughness (on the micro and nano scale) and a coating of some water repellent substance The roughness of a surface is an important factor when creating a superhydrophobic coating [8] To acquire a good combination of the nano-scale and micro-scale structure one can utilize either a bottom up process, building up the surface with new material (e.g nano particles), or a top down process, wearing down the surface in such a way so that the right kind of structure emerges (e.g sand blasting) Figure 1: The contact angle is the angle between the liquid fluid interface and the tangent to the solid interface at the contact line between the three faces Figure 2: Illustration of contact angle versus Gibbs energy RCA is the lowest contact angle for which there exists a local energy minimum ADCA is the highest contact angle for which there exists a local minimum Another vital aspect of creating superhydrophobic coatings is the surface chemistry The surface chemistry dictates the value of the surface energy, the lower the value the more hydrophobic the surface is However, if the adhesion of the top chemical coating to the underlying structure is poor, then the surface will deteriorate quickly when subject to abrasion [9] In some cases the surface properties can even be dynamic, for example the chemistry can be changed by light irradiation [10], an electric field [11], or thermal treatments [12] The goal of the project is to compare different techniques for creating surface structure and applying surface chemistry, and determining which combinations lead to the most durable superhydrophobic surfaces Figure 3: A) Cassie state B) Wenzel state C) A combination of Wenzel and Cassie states 3.1 Materials and Methods Materials The different coatings that were tested are tabulated in table All of the coatings were applied on a small aluminium plate, see figure One of the samples (No 1) has a top down approach to creating the hydrophobic structure, the rest are bottom up Observe that sample No and No have the same hydrophobic material but No has been calcined to improve adhesion Table 1: Superhydrophobic coatings materials These were supplied to us by our supervisors Mikko Tuominen and Mikael Jă arn at SP Stockholm No Superhydrophobic material Fluorosilane Neverwet, commercial nanoparticle-based coating 0.5 wt% Aerosil r972 (Nanoparticle-based coating) 0.5 wt% Aerosil r972 (Nanoparticle-based coating) Fumed SiO2 + fluorosilane Fumed SiO2 + fluorosilane 3.2 Application method/structure creation Sandblasted and anodized before hydrophobization with fluorosilane Spray coating a bottom coat followed by a topcoat Dipcoated and calcined to improve adhesion and then hydrophobized through self assembly of a fluorosilane Dipcoated (No calcination) Dipcoated twice nFog (aerosol wet coating) 60 s Sand abrasion test To study the durability of superhydrophobic coatings we used the sand abrasion test The test involves applying sand to a coated surface from a certain hight and for a certain time (figure 5) Sand was dropped onto the samples from a height of 10 cm, with a particle size of 50-70 µm The samples were mounted at a 45◦ angle Above the sample a sieve was mounted The sieve used in the sand abrasion test was used in order to increase the affected area The downside of the sieve is that the velocity of the sand hitting the samples varies more, without the sieve every grain of sand hitting the surface should in theory have the exact same kinetic energy This means that the Figure 4: An example of what the samples looked like The area of the plate is roughly 7x3 cm average kinetic energy of a grain of sand hitting the surface is harder to calculate The kinetic energy of a single grain of sand hitting the surface of a sample was in the range 0.3 nJ The flow rate of sand onto the sample was 40 g/minute 20 grams of sand were poured Each sample was subjected to around 30 seconds of sand abrasion before performing a measurement Static, receding, advancing contact angle and the roll-off angle was measured after each abrasion This procedure was repeated on each of the surfaces until they were completely worn and the roll-off angle was consistently around 90◦ The contact angles were measured with an OCA contact angle measuring system from Dataphysics producing images like figure The ADCA, RCA and RA were measured by tilting the surface until the drop fell of, this process was filmed and analysed (see figure 10 The RCA is the contact angle on the left side of the drop (if seen from the side and the surface is tilted clockwise, see figure 10) and the ADCA is the contact angle on the right side of the drop just before the drop falls of The drops that were used were of size 5-6 µl, and drops were used per sample per abrasion Figure 5: The sand apparatus that was used to abrade the samples The red cable was used together with copper foil to ground the tip of the plastic tube to prohibit the build-up of static electricity, which would otherwise cause the tube to clog Results In figure to figure the different contact angles and roll-off angles for all the surfaces in the sand test are displayed For all the tested coatings it is the RCA and the RA that are affected the most, and thus are the best indicators of how well a coating performs in this kind of test Observe that sample was significantly better at withstanding the abrasion than the rest, this surface was abraded for a total of 360 seconds before it consistently had a roll-of angle of 90◦ Sample also performed well, withstanding abrasion for a total of 250 seconds Figure 10 displays snapshots of one of the films where receding, advancing and roll-of angle were measured Figure 6: Measurements of roll-of angle (RA) during 140-400 seconds of abrasion A) Sample and B) Sample and C) Sample and Figure 7: Measurements of advancing contact angle (ADCA) during 140-400 seconds of abrasion A) Sample and B) Sample and C) Sample and Figure 8: Measurements of receding contact angle (RCA) during 140-400 seconds of abrasion A) Sample and B) Sample and C) Sample and Figure 9: Measurements of static contact angle during 140-400 seconds of abrasion A) Sample and B) Sample and C) Sample and Figure 10: A) The surface tilted 0◦ B) The surface tilted 10◦ C) The surface tilted 23.3◦ (just before the drop roles of) Discussion When comparing the RA,RCA,ADCA, and static contact angle of the different surfaces, the RA and RCA is affected much more by abrasion than the ADCA and static contact angle This is the reason why we chose to use the RA as an indicator of abrasion and stopped abrading the surfaces when the RA reached 90 degrees consistently Sample withstood the highest amount of abrasion, 360 seconds Recall that sample was calcined, and when compared to sample which was the same coating except it was not calcined, it is evident that the adhesion of the particles (that make up the surface roughness) to the underlying substrate is critical to the coatings durability The second best surface was sample 1, which withstood 250 seconds of abrasion (see figure 6) Sample was made with a top down method, the surface was sand blasted and anodized, removing material from the surface and thus creating the necessary surface structure We think that sample performed well compared to the other samples because of the top down technique, the surface roughness needed was originally part of the bulk of the substrate and thus bonded well with surrounding material The standard deviation of the data tends to increase as the roll off angle reaches 90 degrees, due to a phenomenon called pinning When a droplet is pinned it is in a (partial) Cassie state and its adhesion to the surface is greater than that of other droplets This is a probabilistic phenomenon and depends on where exactly the droplet was placed The RA can vary as much as 85+ degrees, depending on if the droplet is pinning or not When measuring the RA of sample after 90 seconds of abrasion, the RA varied between 1.1 and 90 degrees, with several values in between We found that this was common when the surfaces started to show wear, sample being the most extreme in its range of angles When comparing the RA, ADCA, RCA, and static contact angle of sample and 6, the durability of the two samples are very similar This implies that there is no clear advantage using an aerosol wet coating technique (nFog) over using a dip coating technique, for this particular coating One of the largest problems with the sand test apparatus was the build up of static electricity, causing the sand to flow erratically or not at all through the nozzle This problem was partially solved by grounding the outside of the nozzle, however to fully solve the issue one could use a nozzle made with glass instead of plastic The method of using sand as abrasion material was chosen to imitate the realistic condition that small particles (carried by the wind for example) hit the surface For many applications this kind of abrasion is very relevant and similar sand tests have also been performed by others [9] However it could be interesting to utilize other types of abrasion methods to further study superhydrophobic coatings, to better mimic the different types of abrasions a surface could be exposed to One such method could be an icing-melting cycle where a drop of water freezes and melts on top of the coating The icing-melting abrasion was examined in this project, but due to difficulties with freezing the droplets we decided to focus on the sand abrasion instead Even though it could be difficult to execute, the method could be very relevant for outdoor applications in cold climates and industrial applications such as heat sinks and refrigerators/freezers Another method could consist of a wiping test where some material is wiped across the surface with a constant pressure in order to abrade the coating, which would be appropriate for coatings meant to be used on or in conjunction with textiles When abrading a surface with falling sand, the damage done to the surface structure varies To increase the accuracy of the results, the average of five measurements were used for each data point in figures - When designing the abrasion apparatus we wanted an even flow over a large area, however to achieve this, a large flow of sand was required On the other hand a low flow of sand is desirable since the surfaces tested were very sensitive We compromised by using as low a flow that we deemed appropriate, together with a sieve mounted above the sample to spread the falling sand The amount of sand hitting the sample was measured, and more than 98% of the sand poured into the funnel (figure 5) hit the sample In order get a better representation, several samples with the same coating should be studied in order to lessen the effect of variations in the individual samples However, abrading and measuring the RA, ADCA, etc of a sample is time consuming so the number of different coatings was prioritized over measuring on one type of coating several times The coatings tested in this project have a limited range of applications in their current form due to their relatively poor durability Some of the surfaces showed such poor durability that they would probably have no applications at all in their current state (e.g sample 2,5 and 6) However coating and could perhaps be of use in applications where external abrasion effects are kept to a minimum Another important aspect when considering the applications for these coatings is if they can be easily mass-produced For example, sample could be difficult to mass-produce due to the several steps it takes to create the coating, even though it performs well in this durability test Conclusions In this work the durability of different coatings have been examined Two of the surfaces (sample and 3) withstood significantly more abrasion than the other four samples Sample was calcined to improve adhesion and sample was sand blasted and anodized to create a hydrophobic structure Our findings indicate that calcination and a bottom-up approach to the structure are sound methods of creating more durable superhydrophobic surfaces The roll-off angle and the receding contact angle were the two best indicators of the deterioration of a surface, while the static contact angle and the advancing contact angle varied little with abrasion References [1] W Barthlott and C Neinhuis Purity of the sacred lotus, or escape from contamination in biological surfaces Planta, 202(1):1–8, April 1997 [2] P Jiang, J F Bertone, K S Hwang, and V L Colvin Single-Crystal Colloidal Multilayers of Controlled Thickness Chemistry of Materials, 11(8):2132–2140, August 1999 [3] Michael Nosonovsky and Bharat Bhushan Superhydrophobic surfaces and emerging applications: Nonadhesion, energy, green engineering Current Opinion in Colloid & Interface Science, 14(4):270–280, August 2009 [4] Anish Tuteja, Wonjae Choi, Minglin Ma, Joseph M Mabry, Sarah A Mazzella, Gregory C Rutledge, Gareth H McKinley, and Robert E Cohen Designing Superoleophobic Surfaces Science, 318(5856):1618– 1622, December 2007 [5] Abraham Marmur Soft contact: measurement and interpretation of contact angles Soft Matter, 2(1):12–17, December 2006 [6] Robert N Wenzel Resistance of solid surfaces to wetting by water Industrial & Engineering Chemistry, 28(8):988–994, August 1936 [7] A B D Cassie and S Baxter Wettability of porous surfaces Transactions of the Faraday Society, 40:546, 1944 [8] Anish Tuteja, Wonjae Choi, Joseph M Mabry, Gareth H McKinley, and Robert E Cohen Robust omniphobic surfaces Proceedings of the National Academy of Sciences, 105(47):18200–18205, November 2008 [9] Xu Deng, Lena Mammen, Hans-Jă urgen Butt, and Doris Vollmer Candle Soot as a Template for a Transparent Robust Superamphiphobic Coating Science, 335(6064):67–70, January 2012 [10] Scott Abbott, John Ralston, Geoffrey Reynolds, and Robert Hayes Reversible Wettability of Photoresponsive Pyrimidine-Coated Surfaces Langmuir, 15(26):8923–8928, December 1999 10 [11] Joerg Lahann, Samir Mitragotri, Thanh-Nga Tran, Hiroki Kaido, Jagannathan Sundaram, Insung S Choi, Saskia Hoffer, Gabor A Somorjai, and Robert Langer A reversibly switching surface Science (New York, N.Y.), 299(5605):371–374, January 2003 [12] Woo-Kyung Lee, Lloyd J Whitman, Jungchul Lee, William P King, and Paul E Sheehan The nanopatterning of a stimulus-responsive polymer by thermal dip-pen nanolithography Soft Matter, 4(9):1844–1847, August 2008 11 Appendix Sample zero abrasion 30 seconds 60 seconds 90 seconds 120 seconds 150 seconds 180 seconds 210 seconds 240 seconds Sample zero abrasion 30 seconds 60 seconds 90 seconds 120 seconds 150 seconds Sample zero abrasion 30 seconds 60 seconds 90 seconds 120 seconds 150 seconds 180 seconds 210 seconds 240 seconds 300 seconds 360 seconds Sample zero abrasion 30 seconds 60 seconds 90 seconds 120 seconds 150 seconds Sample zero abrasion 30 seconds 60 seconds 90 seconds 120 seconds Sample zero abrasion 30 seconds 60 seconds 90 seconds 120 seconds Static CA 160,61 153,48 151,71 150,3 149,88 150,18 149,9 145,06 138,75 Static CA avg 159,61 156,176 151,944 151,464 148,534 146,812 148,856 145,494 144,346 Sheet1 std CA 1,338973487 2,192072079 2,37826197 1,688825035 2,043411363 2,272921028 1,772464386 1,391826139 4,726333674 RCA 132,75 147,81 134,43 131,99 127,35 122,59 118,98 121,43 118,98 Static CA 151,85 148,61 143,27 140,41 136,78 137,51 Static CA avg 144,814 146,876 143,086 142,206 139,598 140,77 std CA 6,090897307 3,003486308 2,632931826 2,623267047 2,919909245 2,789659477 RCA 133,43 142,09 135,49 103,81 90,51 112,08 Static CA 161,91 157,39 157,15 157,7 158,98 156,26 160,73 156,62 153,12 155,96 151,78 Static CA avg 161,05 157,402 158,15 157,498 159,264 157,284 157,198 156,271 154,556 154,962 152,072 std CA 1,216223664 0,663867457 0,749366399 1,459595834 0,448029017 1,365258217 2,927325144 1,54005844 1,088407093 1,432626958 1,151941839 RCA 159,04 156,47 153,21 153,98 150,87 141,07 122,51 126,075 130,47 100,12 113,93 Static CA 160,64 153,76 150,41 149,59 Static CA avg 159,956 157,84 152,982 150,226 0 std CA 1,493261531 2,459430828 1,666709333 2,262803571 0 RCA 151,3 129,03 110,56 113,35 0 Static CA 161,64 158,23 158,87 155,95 159,52 139,31 Static CA avg 161,554 159,472 158,892 std CA 0,532710052 1,62216522 1,385016245 155,582 141,064 RCA 155,71 157,48 153,78 119,07 5,650531538 100,41 4,921034444 99,22 Static CA 163,21 162,53 160,73 159,08 154,02 Static CA avg 158,033 162,386 159,4 156,848 154,46 std CA 3,487598744 0,584320118 2,4211774 3,046419209 2,728259518 RCA 116,13 151,97 151,2 143,52 112,21 Page 12 Sample zero abrasion 30 seconds 60 seconds 90 seconds 120 seconds 150 seconds 180 seconds 210 seconds 240 seconds Sample zero abrasion 30 seconds 60 seconds 90 seconds 120 seconds 150 seconds Sample zero abrasion 30 seconds 60 seconds 90 seconds 120 seconds 150 seconds 180 seconds 210 seconds 240 seconds 300 seconds 360 seconds Sample zero abrasion 30 seconds 60 seconds 90 seconds 120 seconds 150 seconds Sample zero abrasion 30 seconds 60 seconds 90 seconds 120 seconds Sample zero abrasion 30 seconds 60 seconds 90 seconds 120 seconds RCA 146,5 143,38 126,62 127,8 123,11 121,99 116,75 116,75 117 RCA 158,99 139,24 133,63 131,75 131,41 122,55 114,76 119,22 115,2 Sheet1 RCA 138,4 143,23 134,79 129,15 129,46 123,18 120,96 115,68 122,51 RCA 140,7 135,66 115,05 132,49 102,33 98,2 RCA 139,25 136,45 137,58 108,01 96,55 89,02 RCA 134,81 137,3 129,37 111,59 102,92 93,66 RCA 144,68 137,08 131,56 126,37 125,9 100,81 RCA 159,93 158,49 152,94 157,11 146,52 149,2 142,16 145,88 128,75 100,59 103,44 RCA 159,68 156,22 152,34 150,67 145,86 137,42 143,14 127,81 115,66 125,25 99,02 RCA 160,4 154,39 156,06 148,04 142,93 143,2 137,79 134,42 121,61 115,42 109,2 RCA 161,07 154,01 150,97 150,98 143,04 133,35 148,59 124,75 117,22 102,61 104,91 RCA 132,98 129,43 105,26 110,28 0 RCA 141,83 121,75 98,38 103,822 0 RCA 146,46 126,13 101,33 104,67 0 RCA 152,74 115,19 108,66 107,57 0 RCA 155,23 160,14 157,26 137,69 109,91 106,75 RCA 156,58 159,28 116,2 95,82 105,04 107,2 RCA 157,48 158,16 155,9 135,89 125,79 101,05 RCA 153,6 155,7 153,74 124,52 149,35 103,38 RCA 149,69 156,62 157,56 127,39 102,46 RCA 147,47 158,13 152,64 139,96 98,66 RCA 138,14 152,99 146,24 118,22 99,78 RCA 146,32 152,99 143,61 141,28 101,1 Page RCA 128,6 140,41 143,57 120,73 131,19 123,69 124,93 112,61 116,97 Sample zero abrasion 30 seconds 60 seconds 90 seconds 120 seconds 150 seconds 180 seconds 210 seconds 240 seconds Sample zero abrasion 30 seconds 60 seconds 90 seconds 120 seconds 150 seconds Sample zero abrasion 30 seconds 60 seconds 90 seconds 120 seconds 150 seconds 180 seconds 210 seconds 240 seconds 300 seconds 360 seconds Sample zero abrasion 30 seconds 60 seconds 90 seconds 120 seconds 150 seconds Sample zero abrasion 30 seconds 60 seconds 90 seconds 120 seconds Sample zero abrasion 30 seconds 60 seconds 90 seconds 120 seconds RCA avg 141,048 142,814 134,608 128,284 128,504 122,8 119,276 117,138 118,132 std RCA 12,06711523 3,316855439 6,023845948 4,576972799 3,427838969 0,651766829 3,926388926 3,373984292 2,789008784 Sheet1 ADCA 161,3 156,33 151,78 160,56 155,1 159,33 163,29 156,12 160,01 RCA avg 138,574 137,716 129,81 116,454 103,642 98,754 std RCA 4,552156632 2,526822115 8,856480678 12,35223381 13,42020007 8,700803411 ADCA 140,49 150,37 141,05 146,83 142 144,7 ADCA 146,2 147,34 144,53 148,19 148,44 144,61 RCA avg 160,024 155,916 153,104 152,156 145,844 140,848 138,838 131,787 122,742 108,798 106,1 std RCA 0,763367539 1,801826851 1,865054959 3,478567234 3,243135828 5,985571819 9,903866417 8,71074308 6,666083558 11,12979649 5,690716124 ADCA 158,58 158,73 158,03 159,29 160,77 158,75 155,29 156,255 158,59 155,58 157,16 ADCA 159,5 157,96 159,68 160,17 158,13 159,92 158,01 160,12 157,58 157,5 158,33 RCA avg 145,062 124,306 104,838 107,9384 0 std RCA 8,003737877 5,948384655 5,038325119 3,95384026 0 ADCA 155,97 162,38 158,61 159,63 0 ADCA 162,12 167,75 157,59 156,02 0 RCA avg 155,72 158,152 147,376 std RCA 1,463881826 1,709420955 17,49147449 120,349 103,52 17,55784817 3,485175749 ADCA 158,64 161 159,53 156,58 158,15 149,57 ADCA 159,86 159,16 158,81 157,76 156,24 146,47 RCA avg 145,405 154,54 150,25 134,074 102,842 std RCA 5,041259763 2,675088784 5,482253186 10,86074951 5,426897825 ADCA 159,51 163,03 151,94 159,46 157,55 ADCA 162,07 162,33 157,69 160,89 155,54 Page ADCA 160,65 156,66 152,26 150,46 155,6 155,62 150,44 159 157,25 Sample zero abrasion 30 seconds 60 seconds 90 seconds 120 seconds 150 seconds 180 seconds 210 seconds 240 seconds Sample zero abrasion 30 seconds 60 seconds 90 seconds 120 seconds 150 seconds Sample zero abrasion 30 seconds 60 seconds 90 seconds 120 seconds 150 seconds 180 seconds 210 seconds 240 seconds 300 seconds 360 seconds Sample zero abrasion 30 seconds 60 seconds 90 seconds 120 seconds 150 seconds Sample zero abrasion 30 seconds 60 seconds 90 seconds 120 seconds Sample zero abrasion 30 seconds 60 seconds 90 seconds 120 seconds ADCA 159,43 156,17 154,97 158,97 156,44 160,19 156,9 155,78 149,85 ADCA 159,49 156,27 156,6 158,95 166,68 155,84 160,7 159,6 158,91 Sheet1 ADCA 160,7 161,05 160,67 151,74 156,37 154,16 157,13 154,79 152,46 ADCA 145,01 146,66 155,96 149,56 144,68 151,43 ADCA 145,88 144,71 146,2 135,44 143,51 142,8 ADCA 150,08 148,39 145,25 138,57 145,55 142,36 ADCA avg 146,99 146,58667 149,13667 141,19 144,58 145,53 ADCA 160,32 157,75 158,81 159,38 160,6 159,51 159,6 158,87 160,01 155,96 157,89 ADCA 162,92 157,45 158,18 158,4 160,46 156,8 158,85 155,3 167,13 156,43 157,2 ADCA 160,87 156,31 156,65 158,97 158,76 157,17 159,7 164,85 157,81 158,2 154,38 ADCA avg 161,37 157,17 157,88 158,91667 159,94 157,82667 159,38333 159,67333 161,65 156,86333 156,49 ADCA 159,71 163,01 161,46 154,98 0 ADCA 159,4 168,3 159,61 156,9 0 ADCA 150,24 159,1 159,42 158,27 0 ADCA avg 156,45 163,47 160,16333 156,71667 0 ADCA 156,35 158,02 160,44 155,89 154,63 152,06 ADCA 160,42 161,48 159,44 157,65 164,48 156,31 ADCA 160,38 159,03 158,62 165,13 161,15 147,23 ADCA avg 159,05 159,51 159,5 ADCA 164,01 164,4 162,02 164,97 152,37 ADCA 152,18 164,2 163,74 161,82 158,66 ADCA 159,75 162,15 153,12 160,05 159,58 ADCA avg 158,64667 163,58333 159,62667 162,28 156,87 Page ADCA avg 159,87333 157,83 157,41333 156,55333 159,83 156,73 158,24333 156,72333 153,74 159,82167 151,86667 Sheet1 Sample zero abrasion 30 seconds 60 seconds 90 seconds 120 seconds 150 seconds 180 seconds 210 seconds 240 seconds Sample zero abrasion 30 seconds 60 seconds 90 seconds 120 seconds 150 seconds Sample zero abrasion 30 seconds 60 seconds 90 seconds 120 seconds 150 seconds 180 seconds 210 seconds 240 seconds 300 seconds 360 seconds Sample zero abrasion 30 seconds 60 seconds 90 seconds 120 seconds 150 seconds Sample zero abrasion 30 seconds 60 seconds 90 seconds 120 seconds Sample zero abrasion 30 seconds 60 seconds 90 seconds 120 seconds std ADCA 0,820749657 2,106580167 3,614488899 4,665397089 4,863015525 2,594064379 4,845623799 2,114833327 4,358976944 RA 11,3 10,4 20,8 27,7 32,4 45,3 41,8 51,6 62,9 RA 7,1 8,5 23,4 23,9 33 49,5 45,9 62,3 56 RA 1,1 12,3 18,4 23,3 23,9 37,3 55,7 55,6 90 std ADCA 3,425853178 2,094285081 5,582998298 6,301576787 2,414752575 3,648102246 RA 9,8 5,5 15,3 40,2 90 42,8 RA 1,7 7,5 21,1 21,3 90 90 RA 1,6 8,2 14,8 31,8 50,9 90 std ADCA 1,634998471 0,88141931 1,114652412 0,645267386 1,211540342 1,390449568 1,809433613 3,764559071 3,975761562 1,09077037 1,540347363 RA 1,1 1,4 2,6 5,3 6,4 22,6 23,25 20,7 36,2 90 RA 0,7 1,9 1,8 5,4 3,8 10,1 6,9 19,8 90 90 RA 1,1 1,4 3,6 4,6 8,7 8,2 20,3 18,5 40 90 std ADCA 4,60668753 3,876489391 1,429080124 1,83388931 0 RA 2,8 23,4 90 49,2 0 RA 8,6 21,1 90 90 0 RA 5,5 25,3 80,8 90 0 RA 1 1,1 0,7 6,5 3,621047117 50,8 3,99501189 90 RA 1,1 0,7 0,8 34,5 90 RA 1,6 0,5 7,4 90 20,1 90 std ADCA 5,182980963 1,039937498 5,227286103 2,165656944 2,869886757 RA 2,4 1,5 1,9 17,7 90 RA 5,1 2,4 2,2 2,5 90 std ADCA 1,712308383 1,450351681 0,716149426 RA 40,6 2,4 1,6 5,8 32,2 Page Sample zero abrasion 30 seconds 60 seconds 90 seconds 120 seconds 150 seconds 180 seconds 210 seconds 240 seconds Sample zero abrasion 30 seconds 60 seconds 90 seconds 120 seconds 150 seconds Sample zero abrasion 30 seconds 60 seconds 90 seconds 120 seconds 150 seconds 180 seconds 210 seconds 240 seconds 300 seconds 360 seconds Sample zero abrasion 30 seconds 60 seconds 90 seconds 120 seconds 150 seconds Sample zero abrasion 30 seconds 60 seconds 90 seconds 120 seconds Sample zero abrasion 30 seconds 60 seconds 90 seconds 120 seconds RA 6,3 9,3 16,6 29 36,1 39,4 36,5 57,7 53 RA 8,2 7,3 8,9 30,8 33,4 41,2 42,9 61,6 90 Sheet1 RA avg 6,8 9,56 17,62 26,94 31,76 42,54 44,56 57,76 70,38 RA 7,4 17 38,3 47,8 90 RA 2,8 7,4 15,9 21,6 30,3 90 RA avg 4,58 7,2 16,82 30,64 61,8 80,56 std RA 3,655407 1,0074721 2,5292291 8,9494693 26,914401 21,108482 RA 0,2 0,6 1,4 3,7 5,8 7,5 9,8 10,1 31,3 26,4 81 RA 0,6 2,1 6,7 13,5 3,8 25,7 25,5 42,6 90 RA avg 0,4 0,9 1,64 2,94 5,56 7,98 10,9 17,25 23,16 47,04 88,2 std RA 0,2828427 0,2345208 0,3361547 0,7797435 0,7700649 3,5772895 7,0078527 8,2908082 5,2628889 24,790885 4,0249224 RA 4,9 28,8 90 90 0 RA 5 27 47,4 90 0 RA avg 5,36 25,12 79,64 81,84 0 std RA 2,0863844 3,009485 18,457736 18,246315 0 RA 1,1 0,8 3,9 7,1 54,3 RA 2,2 1,8 0,8 20,7 1,1 90 RA avg 1,4 1,02 2,1 std RA 0,5049752 0,4969909 2,9631065 23,77 82,86 28,227924 15,965525 RA 6,3 1,5 2,7 90 RA 4,2 2,5 2,2 6,7 90 RA avg 4,5 2,06 2,12 8,34 78,44 std RA 1,6431677 0,5128353 0,4086563 5,7291361 25,848946 Page std RA 3,7094474 1,904731 5,5047252 3,2485381 4,6166005 4,8778069 7,0928133 4,4150878 18,266691 ...Abstract Durability of Superhydrophobic Coatings - Sand Abrasion Test Hugo Harlin & Max Holmberg Teknisk- naturvetenskaplig fakultet UTH-enheten Besöksadress: Ångströmlaboratoriet... assembly of a fluorosilane Dipcoated (No calcination) Dipcoated twice nFog (aerosol wet coating) 60 s Sand abrasion test To study the durability of superhydrophobic coatings we used the sand abrasion. .. 10 displays snapshots of one of the films where receding, advancing and roll -of angle were measured Figure 6: Measurements of roll -of angle (RA) during 14 0-4 00 seconds of abrasion A) Sample and