Classifications

• • C—CHEMISTRY; METALLURGY
  • C09—DYES; PAINTS; POLISHES; NATURAL RESINS; ADHESIVES; COMPOSITIONS NOT OTHERWISE PROVIDED FOR; APPLICATIONS OF MATERIALS NOT OTHERWISE PROVIDED FOR
  • C09D—COATING COMPOSITIONS, e.g. PAINTS, VARNISHES OR LACQUERS; FILLING PASTES; CHEMICAL PAINT OR INK REMOVERS; INKS; CORRECTING FLUIDS; WOODSTAINS; PASTES OR SOLIDS FOR COLOURING OR PRINTING; USE OF MATERIALS THEREFOR
  • C09D183/00—Coating compositions based on macromolecular compounds obtained by reactions forming in the main chain of the macromolecule a linkage containing silicon, with or without sulfur, nitrogen, oxygen, or carbon only; Coating compositions based on derivatives of such polymers
  • C09D183/04—Polysiloxanes
• • C—CHEMISTRY; METALLURGY
  • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
  • C08G—MACROMOLECULAR COMPOUNDS OBTAINED OTHERWISE THAN BY REACTIONS ONLY INVOLVING UNSATURATED CARBON-TO-CARBON BONDS
  • C08G77/00—Macromolecular compounds obtained by reactions forming a linkage containing silicon with or without sulfur, nitrogen, oxygen or carbon in the main chain of the macromolecule
  • C08G77/04—Polysiloxanes
  • C08G77/12—Polysiloxanes containing silicon bound to hydrogen
• • C—CHEMISTRY; METALLURGY
  • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
  • C08G—MACROMOLECULAR COMPOUNDS OBTAINED OTHERWISE THAN BY REACTIONS ONLY INVOLVING UNSATURATED CARBON-TO-CARBON BONDS
  • C08G77/00—Macromolecular compounds obtained by reactions forming a linkage containing silicon with or without sulfur, nitrogen, oxygen or carbon in the main chain of the macromolecule
  • C08G77/04—Polysiloxanes
  • C08G77/20—Polysiloxanes containing silicon bound to unsaturated aliphatic groups

Definitions

• the invention relates to a preparation method of a base suitable for use under the coating so as to obtain superhydrophobic surfaces which are suitable for easy adaptation to the industrial surfaces, has increased mechanical durability and economic life and has high repellency.
• the superhydrophobic coatings that provide many properties such as preventing corrosion, fogging, icing, contamination etc. depending on their liquid repellency properties become very popular.
• the superhydrophobic coatings are such coatings with a contact angle of more than 150 degrees and a rolling angle of less than 10 degrees.
• the rolling angle and contact angle have importance individually.
• the contact angle is important so as not to spread the liquid over the surface.
• the rolling angle is very important for immediately removing the liquid that is dropped on the surface and providing more efficient results in conditions such as icing, fogging and contamination etc. It is clear with the properties provided with these coatings that they can be used in many fields. It has a potential to be used in many fields such as aircraft and aviation industry, paper industry, ceramic industry, packaging industry, textile industry.
• the superhydrophobic coatings have some disadvantages in their applications. The most important of these can be listed as follows; mechanical durability is not at the required level for the application and the transparency of the coating is not sufficiently high. Various studies are performed in the literature so as to eliminate these disadvantages.
• the coating composition contains a fluorinated hydrophobic solvent, a fluorinated hydrophobic polymer and hydrophobic silica nanoparticles.
• a superhydrophobic coating method that comprises the following process steps; reducing the surface energies by modifying the nano-sized hydrophobic particles, preparing the resin by dispersing the modified particles in the polymer matrix, dispersing the resin in a solvent environment with appropriate polarity, applying the resin-solvent mixture to the surface, heating the surface considering the curing temperature of the resin and the evaporation temperature of the solvent and that increases the adhesion of the coating on the surface where it is coated.
• the most commonly used method for the production of the superhydrophobic coatings is to deposit nanoparticles modified with low surface energy molecules on surfaces.
• the topography created by nanoparticles and low surface energy are combined, the superhydrophobic coatings are obtained.
• such coatings with liquid repellency property also exhibit a very weak adhesion to the surface that they are applied.
• it is envisaged as a solution to this is its application by mixing nanoparticles into different polymer matrixes. Unfortunately, only a partial improvement is realized with this approach.
• the polymeric materials used cause a reduction in the water repellency of the coatings.
• the present invention relates to a preparation method of a base suitable for use to improve the durability of the superhydrophobic surfaces which fulfills the abovementioned requirements, eliminates all disadvantages and brings some additional advantages.
• the main aim of the invention is to develop a preparation method of a base suitable for application on a wide range of materials, including glass, textile, leather, plastic, ceramic, metal, concrete, stone, and wood surfaces.
• Another aim of the invention is to provide superhydrophobic surfaces that benefit from the three-dimensional structure of fiber matrix materials and have improved mechanical impact resistance and water repellency.
• the present invention is a preparation method of a base suitable for use to improve the durability of the superhydrophobic surfaces, characterized in that; it comprises the following process steps; i. Preparation of a polymeric liquid mixture ii. Placing a material with a three-dimensional fiber matrix structure to be used as a template iii. Coating said mixture on the fiber matrix material iv. Curing and cooling the mixture v. Separating the cured polymeric mixture from the surface of the fiber matrix material.
• the invention is a preparation method of a base suitable for use to improve the durability of the superhydrophobic surfaces, characterized in that; it comprises the following process steps; i. Preparation of a polymeric liquid mixture ii. Placing a material with a three-dimensional fiber matrix structure to be used as a template iii. Coating said mixture on the fiber matrix material iv. Curing and cooling the mixture v. Separating the cured polymeric mixture from the surface of the fiber matrix material
• the liquid mixture mentioned in the process step (i) has a thermoset structure; it preferably contains polydimethylsiloxane (PDMS).
• the liquid mixture also contains a cross linker, namely a curing agent, preferably it comprises dimethylhydrogen siloxane according to an embodiment of the invention.
• the ratio of PDMS and curing agent is between 10:0.5 to 10:6 by weight.
• the material with said three dimensional fiber matrix materials can be considered as a template containing nanometric and micrometric sized gaps.
• the fiber matrix material is selected from the group consisting of photocopy paper, stone paper, filter paper, straw paper, cardboard, fabric and templates produced by nano-production techniques In other embodiments of the invention; the fiber matrix structure can also be produced synthetically.
• the liquid mixture is coated on the fiber matrix material and it is expected to wet this material. Therefore, it is possible to fill the liquid mixture in the micrometric/nanometric sized channels and gaps in the structure of the fiber matrix material.
• the elastomeric film is formed after the liquid thermoset polymer is poured on the fiber matrix material.
• the curing process mentioned in the process step (iv) is performed between 20°C to 300°C.
• the curing temperature varies depending on the curing time. That is to say, while it can be cured for 24 hours at room temperature, it can be cured at 300°C for approximately 15 minutes.
• the curing time and temperature can be chosen within a wide range.
• the liquid mixture solidifies and shows elastomeric properties and takes the template form. Therefore, the three-dimensional structure of the fiber matrix material (channels, gaps, recesses and protrusions) is transferred to the elastomeric material.
• the elastomeric material whose surface is modified in micrometric size by solidifying is preferably cooled under atmospheric conditions.
• base is obtained by removing the cooled elastomeric material by abrading the fiber matrix material.
• the base prepared by the inventive method is subsequently coated with a coating solution so as to obtain superhydrophobic surface.
• the coating solution contains nanoparticles that are modified with low surface energy ( ⁇ 30 Nnr 1 ) molecules.
• 2 grams of nanoparticles are added into 40 ml. of toluene and mixed with the help of magnetic stirring bar so as to prepare said modified nanoparticles.
• 1 ml. of low surface energy alkyl silane, preferably dodecyltrichlorosilane is added slowly and the mixture is stirred for 3 hours. Centrifugation is carried out for 15 minutes after mixing.
• the modified nanoparticles obtained after centrifugation are dried in an oven at 80°C temperature.
• the drying process is preferably continued for approximately 12 hours.
• Said nanoparticles are selected from the group consisting of hydrophilic silica, titanium dioxide, iron dioxide, zinc oxide nanoparticles. According to the most preferred embodiment, said nanoparticles are hydrophilic silica nanoparticles.
• the coating solution is prepared by dispersing these modified nanoparticles prepared, preferably within ethanol. According to a preferred embodiment of the invention, the coating solution contains silica nanoparticles modified with alkyl silane. Accordingly, the coating solution preferably contains modified nanoparticles in a ratio of 2% by weight. Said dispersion process is provided by the vortex device.
• the coating solution contains at least one wax selected from the group consisting of vegetable waxes, animal waxes and mineral waxes.
• the coating solution contains carnauba.
• carnauba is added into ethanol and mixed on the heating plate by heating the same at 120 e C.
• the coating solution contains carnauba in a ratio of 2% by weight.
• Coating process can be carried out by spin coating, dip coating or spray coating.
• ethanol solution is applied on the elastomeric material by means of spray coating.
• a spray dispenser with a 0.35 mm nozzle diameter is preferably used for spray coating.
• the coating process is preferably performed with 4 bar pressure from a distance of 10-30 cm.
• the coating that contains carnauba is dried, there is another process step, which includes removing the thin film layer on the surface by wearing the same with the help of aluminum foil.
• the contact angle is approximately 140 degrees before the abrasion process, on the other hand it increases up to 168 degrees after the abrasion process.
• the carnauba particles are provided to enter into the channels that are copied on the elastomeric material surface.
• the inventive coating method can be applicable to any surface because there is no physical and chemical limitation on the surface of application. Glass, textiles and leather, plastic, ceramics, metal, walls, stone and wood, electronic products can be listed for these.
• the inventive method is suitable for use in the industries such as textile, automotive, aviation, packaging, and electronics.
• the contact angle decreased to 150° at the end of the 5 th minute and lost its high repellency property.
• the superhydrophobic coating improved by the inventive method can still retain a very high contact angle of 175° after 10 minutes under the sa me conditions.
• the long-term drop impact test when the water droplets freely fall from a height of 30 cm, an impact is formed on the sample surface placed at an angle of 45 e .
• the water droplets that hit the surface at a speed of 2.801 m/s with the free fall of the drops formed an impact on the surface with a pressure effect of -3.922 kPa.
• the superhydrophobic surfaces obtained by the inventive method showed more durability compared to the control groups.
• Another advantage of the inventive method is that when the water repellency (contact angle) of the applied surface decreases, the water repellency property can be increased by repeating the process step (viii) with the advantage provided by the invention.
• This property can be described as follows: The nanoparticles modified with the molecules with low surface energy by means of the morphological structure formed on the elastomeric surface are squeezed between the channels in the morphological structure and it is difficult for them to exit due to the impact applied on the surface. Therefore, the superhydrophobic surfaces obtained by the method of the invention can maintain the properties of high liquid repellency and high impact resistance.

Landscapes

• Chemical & Material Sciences (AREA)
• Chemical Kinetics & Catalysis (AREA)
• Life Sciences & Earth Sciences (AREA)
• Engineering & Computer Science (AREA)
• Materials Engineering (AREA)
• Wood Science & Technology (AREA)
• Organic Chemistry (AREA)
• Application Of Or Painting With Fluid Materials (AREA)
• Reinforced Plastic Materials (AREA)
• Paints Or Removers (AREA)

Applications Claiming Priority (2)

Publications (2)

Family

ID=76575201

Family Applications (1)

Country Status (3)

Families Citing this family (1)

Family Cites Families (6)

• 2019
  • 2019-12-27 TR TR2019/22041A patent/TR201922041A2/tr unknown
• 2020
  • 2020-12-08 EP EP20906023.5A patent/EP4081351A4/de active Pending
  • 2020-12-08 WO PCT/TR2020/051254 patent/WO2021133318A1/en unknown

Also Published As

Similar Documents

Legal Events