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BR-112020024987-B1 - METHOD, ASSEMBLY AND SYSTEM FOR PROVIDING A BASIC STRUCTURE, INDUSTRIAL METHOD, AND MECHANICAL ARM

BR112020024987B1BR 112020024987 B1BR112020024987 B1BR 112020024987B1BR-112020024987-B1

Abstract

The present invention relates to a method and apparatus for providing a base structure at least partially with a cured polymer coating having microscopic polymeric structures. The method comprises the steps of: applying an uncured polymeric material to at least part of the base structure, the uncured polymeric material being electrically charged with a charge having a first sign; providing at least one electrode at a distance above at least part of said uncured polymeric material; charging the at least one electrode with an electrical charge having a second sign opposite to the first sign, thus electrostatically attracting the uncured polymeric material to the at least one electrode and deforming the uncured polymeric material into an uncured structured polymeric material comprising one or more uncured microscopic polymeric structures having a shape; and curing one or more uncured microscopic polymeric structures, thus forming the cured polymer coating.

Inventors

  • AMBER EGON VAN HAUWERMEIREN
  • RUBEN GEUTJENS

Assignees

  • QLAYERS HOLDING B.V

Dates

Publication Date
20260310
Application Date
20190606
Priority Date
20180608

Claims (15)

  1. 1. Method for providing a base structure (1) at least partially with a cured polymer coating (2”) having microscopic polymeric structures (2A), the method comprising the steps of: - applying an uncured polymeric material (2) to at least part of the base structure (1), the uncured polymeric material (2) being electrically charged with a charge having a first sign (S1); - providing at least one electrode (4) at a distance above at least part of said uncured polymeric material (2); - charging the at least one electrode (4) with an electrical charge having a second sign (S2) opposite to the first sign (S1), thus electrostatically attracting uncured polymeric material (2) towards the at least one electrode (4) and deforming the uncured polymeric material (2) into an uncured structured polymeric material (2’) comprising one or more uncured microscopic polymeric structures (2A) having a shape; - curing a or more uncured microscopic polymeric structures (2A), thus forming the cured polymer coating (2”); the method being characterized in that, before or during the curing step of one or more uncured microscopic polymeric structures (2A), the method comprises the step of: - controlling and stabilizing the shape of one or more uncured microscopic polymeric structures (2A), by: - monitoring the occurrence and amperage of a current between the electrode (4) and the uncured microscopic polymeric structures (2A), while at least one electrode (4) is charged; - defining a limit value for said amperage; - when said limit value of amperage is exceeded, at least reducing said amperage by: - reducing the electric charge on the electrode (4) and/or - increasing the distance between the electrode (4) and the uncured microscopic polymeric structure (2A).
  2. 2. Method according to claim 1, characterized in that the current between the uncured microscopic polymer structure (2A) and the electrode (4) is measured by a shunt resistor (5) that is electrically connected in series with the electrode (4).
  3. 3. Method according to claim 1 or 2, characterized in that the limiting amperage value has a magnitude less than 100 nanoamperes.
  4. 4. Method according to any of the preceding claims, characterized in that the electrode (4) is electrically connected to a power source (6) with a connection (7), and in which the electric charge on the electrode (4) is reduced by short-circuiting said connection (7).
  5. 5. Method according to any one of claims 1 to 3, characterized in that the electric charge on the electrode (4) is reduced by altering an output voltage of a power source (6) that charges the electrode (4).
  6. 6. Method according to any of the preceding claims, characterized in that the current between the uncured microscopic polymer structure (2A) and the electrode (4) is reduced by moving the electrode (4) away from the base structure (1) and the uncured microscopic polymer structure (2A).
  7. 7. Method according to any of the preceding claims, characterized in that the curing step of one or more uncured microscopic polymeric structures (2A) is carried out during the stabilization of one or more uncured microscopic polymeric structures (2A).
  8. 8. Method according to any of the preceding claims, characterized in that it further comprises the step of moving the electrode (4) to a different position above the base structure (1), and repeating all other steps of the method.
  9. 9. Method according to claim 8, characterized in that an adapted pattern of microscopic polymeric structures (2A) is formed by repeatedly moving the electrode (4) to a different position above the base structure (1) and repeating all other steps of the method.
  10. 10. Industrial method, characterized by being in accordance with any of the preceding claims.
  11. 11. Assembly (100) for providing a base structure (1) at least partially with a cured polymer coating (2”) having microscopic polymeric structures (2A), the base structure (1) being provided with an uncured polymeric material (2) having an electrical charge of a first sign (S1), the assembly (100) comprising: - at least one electrode (4), configured to be arranged at a distance above at least part of the uncured polymeric material (2); - at least one power source (6), electrically connected with the electrode (4) and configured to charge the electrode (4) with an electrical charge having a second sign (S2) opposite to the first sign (S1) so that, after charging the electrode (4), the uncured polymeric material (2) is electrostatically attracted towards the electrode (4), deforming the uncured polymeric material (2) into uncured structured polymeric material (2’) comprising one or more structures microscopic uncured polymeric structures (2A) having a shape; - a curing source (8), configured to cure the microscopic uncured polymeric structures (2A) and form the cured polymer coating (2”); characterized in that the assembly (100) further comprises: - a control unit (9), configured to control and stabilize the shape of the microscopic uncured polymeric structure (2A), the control unit (9) comprising: - a current measuring unit (10), configured to measure a current between the electrode (4) and the microscopic uncured polymeric structure (2A) and arranged in communication with the control unit (9), wherein the control unit (9) allows the setting of a limit value, and wherein the control unit (9) is configured to: - reduce the load on the electrode (4) and/or - increase the distance between the electrode (4) and the microscopic uncured polymeric structure (2A) when said current exceeds said limit value.
  12. 12. Assembly according to claim 11, characterized in that the control unit (9) includes a switch (11) configured to short-circuit the electrical connection (7) between the power source (6) and the electrode (4).
  13. 13. Assembly according to claim 11 or 12, characterized in that the control unit (9) includes an actuator (12) operatively connected to the electrode (4), the actuator (12) being configured to move the electrode (4) away from the uncured microscopic polymer structure (4).
  14. 14. System (200) for providing a base structure (1) at least partially with a cured polymer coating (2”) having microscopic polymeric structures (2A), the system characterized in that it comprises: - a polymer application device (13) configured to apply uncured polymeric material (2) having an electrical charge to a base structure (1) and - the assembly (100) as defined in any one of claims 11 to 13.
  15. 15. Mechanical arm (300), characterized in that it comprises the assembly (100) as defined in any one of claims 11 to 13 and/or the system (200) as defined in claim 14.

Description

[001] The present invention relates to a method, an assembly and a system for providing a base structure at least partially with a cured polymer coating having microscopic polymeric structures. [002] It has been known for several decades that specifically molded coatings on surfaces can help, for example, to reduce the drag on that surface. For example, when analyzing a shark's skin on a microscopic scale, it can be observed that it consists of RIBLETS (ridges or ribs), parallel to each other lengthwise. These RIBLETS help reduce the shark's drag as it swims in the water. These microscopic patterns are observed throughout nature, for many different applications. Drag reduction is mentioned here only as one example. Other examples may include a self-cleaning coating, an anti-graffiti coating, an anti-fouling coating, or a hygroscopic coating. [003] Also, for several decades, it has been desirable to apply such coatings, for example, polymer coatings, on a microscopic scale to man-made items, for example, vehicles including cars, racing cars, airplanes, ships, bicycles or, for example, wind turbine blades, for example, to reduce the drag of such man-made items. Although many attempts have previously been made to apply such coatings, suitable commercially applicable methods have not been verified in the past. [004] In the scientific paper “Micro and nano-patterns created by means of electro-hydrodynamic instabilities”, published in the journal Nano Today in 2009, Wu and Russel describe a method for forming a cured polymer coating on a base structure. The method consists of rotating the coating from a thin layer of polymer onto a silicon substrate, placing a top electrode on top of the polymer film, heating the entire system above the glass transition temperature of the polymer and imposing an external voltage, waiting for seconds to weeks until a pattern formation forms and freezing said pattern formation by rapidly cooling the system back to room temperature. [005] According to the article, this method suffers from serious instabilities in the formation of polymer structures. According to the article, the polymer structures formed by this method have a loss of order for large surfaces, that is, the patterns formed by this method are irregular when applied to large surfaces. This makes the described method unsuitable for large-scale (industrial) application. [006] It is an object of the invention to overcome at least partially the instabilities of the method described above. More specifically, it is an object of the present invention to provide a more reliable, repeatable and/or predictable method for providing a base structure at least partially with a cured or frozen polymer coating. [007] Therefore, according to the invention, the method of claim 1 is presented. [008] The invention, therefore, in other words, relates to a method for providing a base structure at least partially with a cured polymer coating having microscopic polymeric structures, the method comprising the steps of: - applying an uncured polymeric material to at least part of the base structure, the uncured polymeric material being electrically charged with a charge having a first sign; - providing at least one electrode at a distance above at least part of said uncured polymeric material; - charging at least one electrode with an electric charge that has a second sign opposite to the first sign, thus electrostatically attracting the uncured polymeric material towards the at least one electrode and deforming the uncured polymeric material into an uncured structured polymeric material comprising one or more microscopic polymeric structures having a shape; - controlling and stabilizing the shape of one or more uncured microscopic polymeric structures by: - monitoring the occurrence and amperage of a current between the electrode and the uncured microscopic polymeric structures while the at least one electrode is charged; - defining a limit value for said amperage; - when said limit value of amperage is exceeded, at least reducing said amperage by: - reducing the charge on the electrode and/or - increasing the distance between the electrode and the uncured microscopic polymeric structure, and - curing one or more uncured microscopic polymeric structures, thus forming the cured polymer coating. [009] In known methods for forming a cured polymer coating, it is not possible to obtain cured microscopic polymer structures in a consistent and predictable manner. In the article by Wu and Russel, it is stated that “polymer microstructures are far from equilibrium” and that “to date, there is no convincing experimental distinction between “perfect” and “leaky” dielectric models”. Although the previous technique has shown successful formation of cured microscopic polymer structures, the shape of these structures is unpredictable and inconsistent. [0010] For industrial-scale applications, however, reliable, reproducible, and predictable formats and standa