Surface structure for fluid handling

Abstract

The present disclosure describes surface coatings and methods of applying surface coatings for improving the performance of fluid handling techniques. The surface coatings can provide an increase in the force applied to the fluid, better accuracy of fluid position, improved reliability of fluid movement, an increase in the maximum value of the fluid movement speed, a resilience against fouling of the surface, and a resistance against pinning of the fluid. Further, the present disclosure describes a fluid handling device having a surface coating with improved fluid handling performance.

Description

Technical Field

[0001] Cross-reference This application claims the benefit of U.S. Provisional Application No. 63 / 350,835, filed on Jun. 9, 2022, which is hereby incorporated by reference herein in its entirety. Technical Background

[0002] A coating is a covering that is usually applied to the surface of an object, often referred to as a substrate. The purpose of applying a coating can be decorative, functional, or both.

[0003] Functional coatings can be applied to change the surface properties of a substrate, such as adhesion, wettability, corrosion resistance, and wear resistance. In other cases, for example, in semiconductor device manufacturing (where the substrate is a wafer), the coating adds completely new properties, such as magnetic response or conductivity, and forms an essential part of the final product.

[0004] Many industrial coating processes involve the application of a thin film of a functional material to a substrate, such as paper, fabric, film, foil, or sheet stock.

[0005] The coating can be applied as a liquid, gas, or solid, such as a powder coating.

Summary of the Invention

[0006] The present disclosure generally relates to surface coatings for contacting fluids. Although surface coatings for fluid manipulation, such as electro-wetting devices, are specifically mentioned, embodiments of the present disclosure can include additional uses and applications, such as medical devices, implants, laboratory equipment, and electromechanical devices.

[0007] In one aspect, the present disclosure provides a method of coating a surface for contacting a fluid. The method may include applying a film layer to the surface. In some embodiments, the film layer is non-textured. The method may include applying a liquid layer to the film layer. In some embodiments, the liquid layer has a viscosity in the range of about 0.5 centistokes (cSt) to about 100 cSt. In some embodiments, the liquid layer has a viscosity in the range of about 0 cSt to about 20 cSt. In some embodiments, the liquid layer has a viscosity in the range of about 5 cSt to about 20 cSt. In some embodiments, the liquid layer has a viscosity in the range of about 0.5 cSt to about 20 cSt.

[0008] In some embodiments, the liquid layer has an average initial thickness in the range of about 0.01 micrometers (μm) to about 500 μm. In some embodiments, the liquid layer has an average initial thickness in the range of about 10 μm to about 1000 μm.

[0009] In some embodiments, the film layer has a Ra of about 100 μm to about 0 μm. In some embodiments, the film layer has a Ra of about 100 nanometers (nm) to about 0 nm. In some embodiments, the film layer has a Ra of about 1000 nanometers (nm) to about 0 nm.

[0010] In some embodiments, the liquid layer is a lubricating layer. In some embodiments, the lubricating layer is a hydrocarbon layer, a silicone layer, a fluorinated layer, or a combination thereof. In some embodiments, the lubricating layer is polydimethylsiloxane, polymethylhydrogen siloxane / hydrogen silicone oil, aminosilicone oil, phenylmethyl silicone oil, diphenyl silicone oil, vinyl silicone oil, hydroxy silicone oil, cyclopolysiloxane, polyalkylene oxide silicone, silicone resin, perfluoropolyether (PFPE), perfluoroalkane, fluorinated ionic fluid, fluorinated silicone oil, perfluoroalkyl ether, perfluorotri-n-butylamine (FC-40), hydrofluoroether (HFE) liquid, ionic liquid, mineral oil, ferrofluids, polyphenyl ether, vegetable oil, esters of saturated fatty acids and dibasic acids, grease, fatty acid, triglyceride, polyalphaolefin, polyglycol hydrocarbon, other alkanes, or other non-hydrocarbon synthetic oils.

[0011] In some embodiments, the liquid layer further comprises at least one additive. In some embodiments, the at least one additive is a rheology modifier, a filler, a solvent, a surfactant, a dye, or a combination thereof.

[0012] In some embodiments, the liquid layer can diffuse into the film layer and swell the film layer.

[0013] In some embodiments, the liquid layer has a static contact angle with the film layer of from about 10 degrees to about 0 degrees. In some embodiments, the liquid layer has a static contact angle with the film layer of from about 5 degrees to about 0 degrees.

[0014] In some embodiments, the film layer comprises one or more polymer films, inorganic films, composite films, or combinations thereof. In some embodiments, the film layer comprises polyethylene, polypropylene, polystyrene, polyetheretherketone (PEEK), polyimide, polyacetal, polysulfone, polyphenylene ether, polyphenylene sulfide (PPS), polyvinyl chloride, synthetic rubber, natural rubber, neoprene, nylon, polyacrylonitrile, polyvinyl butyral, silicone, parafilm, polyethylene terephthalate, polybutylene terephthalate, polyamide, polyoxymethylene, polycarbonate, polymethylpentene, polyphenylene oxide (polyphenylene ether), polyphthalamide (PPA), polylactic acid, synthetic cellulose ether (e.g., methyl cellulose, ethyl cellulose, propyl cellulose, hydroxyethyl cellulose, hydroxyethyl cellulose, hydroxypropyl cellulose (HPC), hydroxyethylmethyl cellulose, hydroxypropylmethyl cellulose (HPMC), ethylhydroxyethyl cellulose), paraffin, microcrystalline wax, epoxy, polytetrafluoroethylene (PTFE), tetrafluoroethylene (TFE), fluorinated ethylene propylene copolymer (FEP), polyvinylidene fluoride (PVDF), perfluoroalkoxy tetrafluoroethylene copolymer (PFA), perfluoromethyl vinyl ether copolymer (MFA), ethylene chlorotrifluoroethylene copolymer (ECTFE), ethylene-tetrafluoroethylene copolymer (ETFE), perfluoropolyether (PFPE), polychlorotetrafluoroethylene (PCTFE), ceramic, borosilicate glass, quartz, alumina, silica, clay mineral, bentonite, kaolinite, vermiculite, graphite, molybdenum disulfide, mica, boron nitride, sodium formate, sodium oleate, sodium palmitate, sodium sulfate, sodium alginate, or any other polymer or ceramic material, or combinations thereof.

[0015] In some embodiments, the method further includes a step of modifying the film layer. In some embodiments, the modification includes either surface functionalization or the application of a secondary coating. In some embodiments, the modification increases the affinity of the liquid layer for the film layer.

[0016] In some embodiments, the thickness of the film layer is from about 0.1 μm to about 1000 μm.

[0017] In some embodiments, some or all of the surface coating may be removed or replaced. In some embodiments, the surface coating may be permanent.

[0018] In some embodiments, the surface coating is applied to a surface intended to contact a fluid. In some embodiments, the surface coating is applied to a cannula, connector, catheter (e.g., central line, peripherally inserted central catheter (PICC) line, urinary, vascular, peritoneal dialysis, and central venous catheter), catheter connector (e.g., Leur-Lok and needleless connector), clamp, skin hook, cuff, retractor, shunt, needle, capillary, endotracheal tube, ventilator, associated ventilator tubing, drug delivery medium, syringe, microscope slide, plate, film, laboratory work surface, well, well plate, Petri dish, tile, jar, flask, beaker, vial, test tube, tubing connector, column, container, cuvette, bottle, drum, vat, tank, organ, organ implant, or organ component (e.g., intrauterine contraceptive device, defibrillator, cornea, breast, artificial knee joint, and artificial hip implant), artificial organ or its component (e.g., heart valve, ventricular assist device, total artificial heart, artificial inner ear implant, visual prosthesis, and their components), dental tool, dental implant (e.g., root form, plate form, and subperiosteal implant), biosensor (e.g., glucose and insulin monitor, blood oxygen sensor, hemoglobin sensor, biological microelectromechanical devices (bioMEM), sepsis diagnostic sensor, and other protein and enzyme sensors), bioelectrode, endoscope (hysteroscope, cystoscope, amnioscope, laparoscope, gastroscope, enteroscope, bronchoscope, esophagoscope, nasal scope, arthroscope, proctoscope, colonoscope, nephroscope, angioscope, thoracoscope, esophagoscope, laryngoscope, and encephalo scope), wound dressing (e.g., bandage, suture, staple), and combinations thereof.

[0019] In another aspect, the present disclosure provides a surface coating for contacting a fluid. The surface coating may include a film layer. In some embodiments, the film layer is not textured. The surface coating may include a liquid layer. In some embodiments, the liquid layer has a viscosity in the range of about 0.5 centistokes (cSt) to about 100 cSt. In some embodiments, the liquid layer has a viscosity in the range of about 0 cSt to about 20 cSt. In some embodiments, the liquid layer has a viscosity in the range of about 5 cSt to about 20 cSt. In some embodiments, the liquid layer has a viscosity in the range of about 0.5 cSt to about 20 cSt.

[0020] In some embodiments, the liquid layer has an average initial thickness in the range of about 0.01 micrometers (μm) to about 500 μm. In some embodiments, the liquid layer has an average initial thickness in the range of about 10 μm to about 1000 μm.

[0021] In some embodiments, the film layer has a Ra in the range of about 100 μm to about 0 μm. In some embodiments, the film layer has a Ra in the range of about 100 nanometers (nm) to about 0 nm.

[0022] In some embodiments, the liquid layer is a lubricating layer. In some embodiments, the lubricating layer is a hydrocarbon layer, a silicone layer, a fluorinated layer, or a combination thereof. In some embodiments, the lubricating layer is polydimethylsiloxane, polymethylhydrogen siloxane / hydrogen silicone oil, aminosilicone oil, phenylmethyl silicone oil, diphenyl silicone oil, vinyl silicone oil, hydroxysilicone oil, cyclopolysiloxane, polyalkylene oxide silicone, silicone resin, perfluoropolyether (PFPE), perfluoroalkane, fluorinated ionic fluid, fluorinated silicone oil, perfluoroalkyl ether, perfluorotri-n-butylamine (FC-40), hydrofluoroether (HFE) liquid, ionic liquid, mineral oil, ferromagnetic fluid, polyphenyl ether, vegetable oil, esters of saturated fatty acids and dibasic acids, grease, fatty acid, triglyceride, polyalphaolefin, polyglycol hydrocarbon, other alkanes, or other non-hydrocarbon synthetic oils.

[0023] In some embodiments, the lubricating layer further comprises at least one additive. In some embodiments, the at least one additive is a rheology modifier, a filler, a solvent, a surfactant, a dye, or a combination thereof.

[0024] In some embodiments, the liquid layer can diffuse into the film layer and swell the film layer. In some embodiments, the liquid layer has a static contact angle with the film layer of about 10 degrees or less. In some embodiments, the liquid layer has a static contact angle with the film layer of about 5 degrees or less.

[0025] In some embodiments, the film layer comprises one or more polymer films, inorganic films, composite films, or combinations thereof. In some embodiments, the film layer comprises polyethylene, polypropylene, polystyrene, polyether ether ketone (PEEK), polyimide, polyacetal, polysulfone, polyphenylene ether, polyphenylene sulfide (PPS), polyvinyl chloride, synthetic rubber, natural rubber, neoprene, nylon, polyacrylonitrile, polyvinyl butyral, silicone, parafilm, polyethylene terephthalate, polybutylene terephthalate, polyamide, polyoxymethylene, polycarbonate, polymethylpentene, polyphenylene oxide (polyphenylene ether), polyphthalamide (PPA), polylactic acid, synthetic cellulose ether (e.g., methylcellulose, ethylcellulose, propylcellulose, hydroxyethylcellulose, hydroxyethylcellulose, hydroxypropylcellulose (HPC), hydroxyethylmethylcellulose, hydroxypropylmethylcellulose (HPMC), ethylhydroxyethylcellulose), paraffin, microcrystalline wax, epoxy, polytetrafluoroethylene (PTFE), tetrafluoroethylene (TFE), fluorinated ethylene propylene copolymer (FEP), polyvinylidene fluoride (PVDF), perfluoroalkoxy tetrafluoroethylene copolymer (PFA), perfluoromethyl vinyl ether copolymer (MFA), ethylene chlorotrifluoroethylene copolymer (ECTFE), ethylene-tetrafluoroethylene copolymer (ETFE), perfluoropolyether (PFPE), polychlorotetrafluoroethylene (PCTFE), ceramic, borosilicate glass, quartz, alumina, silica, clay mineral, bentonite, kaolinite, vermiculite, graphite, molybdenum disulfide, mica, boron nitride, sodium formate, sodium oleate, sodium palmitate, sodium sulfate, sodium alginate, or any other polymer or ceramic material.

[0026] In some embodiments, the film layer is modified. In some embodiments, the modified film layer includes either a functionalized surface or a secondary coating. In some embodiments, the modified film layer has a high affinity with the liquid layer.

[0027] In some embodiments, the thickness of the film layer is on the order of 0.1 μm to 1000 μm.

[0028] In some embodiments, some or all of the coating can be removed or replaced. In some embodiments, the coating can be permanent.

[0029] In some embodiments, the coating is applied to a surface intended to be in contact with a fluid. In some embodiments, the coating is applied to the surface of a cannula, connector, catheter (e.g., central line, peripherally inserted central catheter (PICC) line, urinary, vascular, peritoneal dialysis, and central venous catheter), catheter connector (e.g., Leur-Lok and needleless connector), clamp, skin hook, cuff, retractor, shunt, needle, capillary, endotracheal tube, ventilator, associated ventilator tube, drug delivery medium, syringe, microscope slide, plate, film, laboratory work surface, well, well plate, Petri dish, tile, jar, flask, beaker, vial, test tube, tube connector, column, container, cuvette, bottle, drum, vat, tank, organ, organ implant, or organ component (e.g., intrauterine contraceptive device, defibrillator, cornea, breast, artificial knee joint, and artificial hip implant), artificial organ or its components (e.g., heart valve, ventricular assist device, total artificial heart, cochlear implant, visual prosthesis, and their components), dental tool, dental implant (e.g., root type, plate type, and subperiosteal implant), biosensor (e.g., glucose and insulin monitor, blood oxygen sensor, hemoglobin sensor, bioelectromechanical device (bioMEM), sepsis diagnostic sensor, and other protein and enzyme sensors), bioelectrode, endoscope (hysteroscope, cystoscope, amnioscope, laparoscope, gastroscope, enteroscope, bronchoscope, esophagoscope, nasal endoscope, arthroscope, proctoscope, colonoscope, nephroscope, angioscope, thoracoscope, esophagoscope, laryngoscope, and brain trough scope), wound dressing (e.g., bandage, suture, staple), and combinations thereof.

[0030] In another aspect, the present disclosure provides an apparatus for fluid manipulation. In some embodiments, the apparatus includes a substrate comprising one or more electrodes. In some embodiments, the apparatus includes a first surface on the substrate. In some embodiments, the first surface includes a surface coating. In some embodiments, the surface coating includes a film layer and a liquid layer.

[0031] In some embodiments, the substrate further includes a sealant layer. In some embodiments, the sealant layer includes a fluoropolymer, polyurethane, acrylic, silicone, polyolefin, parylene, or a combination thereof.

[0032] In some embodiments, the first surface is flat, curved, tubular, horizontal, vertical, or any combination thereof.

[0033] In some embodiments, the device further includes a second surface parallel to the first surface.

[0034] In some embodiments, the device further includes a gap-filling liquid between the substrate and the first surface. In some embodiments, the gap-filling liquid forms a displaced volume between the substrate and the first surface. In some embodiments, the displaced volume has a height of about 0.01 μm to about 500 μm. In some embodiments, the gap-filling liquid is a gel, paste, grease, high-viscosity oil, low-viscosity oil, or a combination. In some embodiments, the gap-filling liquid is a silicone paste, lithium grease, silicone grease, thermal paste, or dyed grease.

[0035] In some embodiments, the gap-filling liquid is a capillary liquid. In some embodiments, the capillary liquid has a contact angle with the film layer of about 5 degrees to about 0 degrees. In some embodiments, the capillary liquid has a contact angle with the film layer of about 1 degree to about 0 degrees. In some embodiments, the capillary liquid has a contact angle with the substrate or the sealant layer of about 5 degrees to about 0 degrees. In some embodiments, the capillary liquid has a contact angle with the substrate or the sealant layer of about 1 degree to about 0 degrees.

[0036] In some embodiments, the capillary liquid is a hydrocarbon oil, silicone oil, fluorinated oil, or liquid acrylate.

[0037] In some embodiments, the gap filling liquid further comprises at least one additive. In some embodiments, the at least one additive is a rheology modifier, a filler, a solvent, a surfactant, a dye, or a combination thereof.

[0038] In some embodiments, the gap filling liquid is either an insulating liquid or a conductive liquid.

[0039] In some embodiments, the first surface is modified. In some embodiments, the modified first surface comprises either a functionalized surface or a secondary coating. In some embodiments, the modified first surface has a higher affinity for the gap filling liquid.

[0040] In some embodiments, the device further comprises a vacuum between the substrate and the first surface.

[0041] In some embodiments, the first surface of the device is from about 0.0001 cm 2 to about 10000 cm 2 in working area.

[0042] In some embodiments, the device further comprises a frame configured to support the first surface.

[0043] In some embodiments, the first surface of the device is configured to contact a fluid to be manipulated. In some embodiments, the device is configured to manipulate a fluid in contact with the first surface. In some embodiments, the fluid to be manipulated comprises inorganic ions, organic ions, proteins, DNA, RNA, surfactants, oil droplets, magnetic beads, nanoparticles, microparticles, polymers, organic compounds, hormones, or a combination thereof. In some embodiments, the fluid to be manipulated comprises water, ethanol, isopropanol, methanol, acetone, formaldehyde, methyl ethyl ketone, acetamide, ethylene glycol, propylene glycol, dimethyl sulfoxide, dimethylformamide, acetic acid, glycerol, or a combination thereof.

[0044] Further aspects and advantages of the present disclosure will become readily apparent to those skilled in the art from the following detailed description, which shows and describes only exemplary embodiments of the present disclosure. As will be understood, the present disclosure is capable of other embodiments and different embodiments, and various details thereof are capable of being modified in various obvious respects without departing from the present disclosure. Accordingly, the drawings and description are to be regarded as illustrative in nature and not as restrictive.

[0045] Incorporation by reference All publications, patents, and patent applications mentioned in this specification are hereby incorporated by reference into this specification to the same extent as if each individual publication, patent, or patent application was specifically and individually indicated to be incorporated by reference. To the extent that the incorporated publications and patents or patent applications conflict with the present disclosure contained in this specification, this specification is intended to supersede and / or take precedence over any such conflicting material.

[0046] This specification hereby incorporates by reference in their entirety U.S. Patent Application No. 16 / 287,023, filed on February 27, 2019, International Application No. PCT / US2020 / 048241, filed on August 27, 2020, and International Application No. PCT / US2022 / 018549, filed on March 2, 2022. BRIEF DESCRIPTION OF THE DRAWINGS

[0047] The novel features of the invention are set forth with particularity in the appended claims. A better understanding of the features and advantages of the invention will be obtained from the following detailed description that describes exemplary embodiments, and the principles of the invention and the accompanying drawings (further. The terms "Figure" and "FIG" are used herein).

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[0048] In the following detailed description, reference is made to the accompanying drawings which form a part hereof. In the drawings, like symbols typically identify like components, unless the context dictates otherwise. The exemplary embodiments described in the detailed description, drawings, and claims are not meant to be limiting. Other embodiments may be utilized and other changes may be made without departing from the scope of the subject matter presented herein. It will be readily understood that the aspects of the present disclosure generally described herein and illustrated in the drawings can be arranged, substituted, combined, separated, and designed in a wide variety of different configurations, all of which are explicitly contemplated herein.

[0049] Specific embodiments and examples are disclosed below, but the subject matter of the present invention extends beyond the specifically disclosed embodiments to other alternative embodiments and / or uses, and their modifications and equivalents. Accordingly, the claims appended hereto are not limited by any of the specific embodiments described below. For example, in any method or process disclosed herein, the acts or operations of the method or process can be performed in any suitable order and are not necessarily limited to any particular disclosed order. The various operations may be described serially as a plurality of distinct operations in a way that may be helpful in understanding some embodiments, but the order of description should not be construed as implying that these operations are order-dependent. Further, the structures, systems, and / or devices described herein may be embodied as integrated components or as separate components.

[0050] For purposes of comparing various embodiments, some aspects and advantages of these embodiments are described. Not necessarily all such aspects or advantages are achieved by any particular embodiment. Thus, for example, the various embodiments may be implemented in a way that achieves or optimizes one advantage or group of advantages taught herein without necessarily achieving other aspects or advantages that may also be taught or suggested herein.

[0051] The present disclosure describes surface coatings and methods of applying surface coatings for improving the performance of fluid handling techniques. The surface coatings of the present disclosure can provide an increase in the force applied to a fluid, better fluid position accuracy, improved reliability of fluid movement, an increase in the maximum speed of fluid movement, resilience against surface contamination, resistance to fluid pinning, and faster heat transfer.

[0052] The chemical properties and texture of the surface coating affect the ease of fluid manipulation. As a result of the chemical composition and physical texture, a fluid on the surface can experience two phenomena when manipulated: pinning and contact angle hysteresis. Pinning occurs when a fluid or its components, such as DNA or magnetic beads, adhere to surface defects when it is being manipulated. Contact angle hysteresis is the difference between the advancing contact angle and the receding contact angle of a moving fluid. In an electrowetting device, droplet pinning and high contact angle hysteresis reduce efficiency because higher voltages are required for fluid manipulation and satellite droplets can be left behind. FIG. 1 is a diagram showing a fluid on a surface experiencing pinning and contact angle hysteresis.

[0053] One way to reduce pinning and contact angle hysteresis involves applying a lubricating fluid onto a textured or porous surface, where the surface texturing helps support the lubricating fluid. However, textured surfaces can be expensive and time-consuming to manufacture, which hinders their use with large quantities of consumables. When used as reusable surfaces, textured surfaces can lead to cross-sample contamination. Quality control of textured surfaces with nanopatterned or micropatterned surfaces can also be difficult. Surface features can be easily damaged after manufacture. Damage to these textured surfaces can cause pinning and fouling. Undamaged textured surfaces can also exhibit fouling, unwanted droplet pinning, and contact angle hysteresis. All of these phenomena can negatively impact the performance of fluid manipulation.

[0054] The surface coating of the present disclosure is smooth and non-porous, enabling low-cost, high-performance, durable, replaceable or permanent surfaces, and can be used with fluid handling techniques such as electro-wetting for various applications including the processing of biological samples and chemical synthesis. The surface coating includes an untextured layer or smooth film layer and a liquid layer that acts as a lubricant to reduce pinning and contact angle hysteresis. Since the film layer is untextured, the liquid layer needs to be moderately viscous to prevent displacement of the liquid layer by the manipulated fluid while minimizing drag.

[0055] Definitions Unless otherwise defined, all technical terms, notations, and other technical, scientific, or specialized terms used herein are intended to have the same meaning as commonly understood by one of ordinary skill in the art to which the claimed subject matter pertains. In some cases, terms with commonly understood meanings are defined herein for clarity and / or for ease of reference, and the inclusion of such definitions herein should not necessarily be construed as representing a substantial difference from what is generally understood in the art.

[0056] Throughout this application, various embodiments may be presented in a variety of forms. It should be understood that the description in range format is merely for convenience and brevity and should not be construed as an inflexible limitation on the scope of the present disclosure. Accordingly, the description of a range should be considered to specifically disclose all possible sub-ranges, as well as the individual numerical values within that range. For example, a description of a range such as 1 to 6 should be considered to specifically disclose sub-ranges such as 1 to 3, 1 to 4, 1 to 5, 2 to 4, 2 to 6, 3 to 6, as well as the individual numbers within that range, for example, 1, 2, 3, 4, 5, and 6. This applies regardless of the breadth of the range.

[0057] As used in this specification and the claims of this patent, the singular forms "a", "an", and "the" include plural references unless the context clearly dictates otherwise. For example, the term "a sample" includes a plurality of samples and combinations thereof.

[0058] The terms "determining", "measuring", "evaluating", "assessing", "assaying", and "analyzing" are often used interchangeably herein to refer to forms of measurement. These terms include determining whether an element is present (e.g., detecting). These terms can include quantitative, qualitative, or both quantitative and qualitative determinations. Evaluation can be relative or absolute. "Detecting the presence of" can, depending on the context, include determining the amount of something that is present in addition to determining whether it is present or absent.

[0059] As used herein, the terms "about" or "approximately", when referring to a measurable value such as an amount or concentration, mean including a variation of up to 20%, 10%, 5%, 1%, 0.5%, or even 0.1% of the specified amount. For example, "about" can mean plus or minus 10% according to practices in the art. Alternatively, "about" can mean a range of plus or minus 20%, plus or minus 10%, plus or minus 5%, or plus or minus 1% of a given value. Alternatively, particularly with respect to biological systems or processes, the term can mean within an order of magnitude of the value, up to 5-fold, or up to 2-fold. Where a particular value may be recited in the present application and claims, unless otherwise stated, the term "about" can be assumed to include an acceptable error range for the particular value. Also, ranges, sub-ranges, or both can be provided, and a range or sub-range can include the endpoints of the range or sub-range.

[0060] When a value is recited as a range, such disclosure is understood to include all possible sub-ranges within such range, as well as the disclosure of specific numerical values that fall within such range, whether or not such specific numerical values or specific sub-ranges are explicitly recited.

[0061] The terms “comprise”, “have”, and “include” are open-ended linking verbs. Any one or more of the morphological forms or tenses of these verbs, such as “comprises”, “comprising”, “has”, “having”, “includes”, “including”, etc., are also open-ended. For example, any method that “comprises”, “has”, or “includes” one or more steps is not limited to having only those one or more steps, but also includes other unrecited steps.

[0062] As used herein, the term “droplet” generally refers to a discrete volume or finite volume of a fluid (e.g., a liquid). A droplet can be produced by one phase separated from another phase by an interface. A droplet can be the first phase phase-separated from another phase. A droplet can contain a single phase or multiple phases (e.g., an aqueous phase containing a polymer or an emulsion). A droplet can be a liquid phase disposed adjacent to a surface and in contact with a separate phase (e.g., a gas phase such as air).

[0063] The term "biological sample", as used herein, generally refers to biological material. Such biological material may exhibit or be bioactive. Such biological material can be or include deoxyribonucleic acid (DNA) molecules, ribonucleic acid (RNA) molecules, polypeptides (e.g., proteins), or any combination thereof. A biological sample (or sample) can be a tissue sample such as a biopsy, core biopsy, needle aspiration, or fine needle aspiration. The sample can be a fluid sample such as a blood sample, urine sample, fecal sample, or saliva sample. The sample can be a skin sample. The sample can be a cheek swab. The sample can be a plasma or serum sample. The sample can be a plant-derived sample, water sample or soil sample. The sample can be extraterrestrial. An extraterrestrial sample can contain biological material. The sample can be a cell-free (or acellular) sample. A cell-free sample can contain extracellular polynucleotides. Extracellular polynucleotides can be isolated from a body sample selected from the group consisting of blood, plasma, serum, urine, saliva, mucosal excretions, sputum, feces and tears. The sample can contain eukaryotic cells or a plurality thereof. The sample can contain prokaryotic cells or a plurality thereof. The sample can contain viruses. The sample can contain compounds derived from organisms. The sample can be plant-derived. The sample can be animal-derived. The sample can be derived from an animal suspected of having a disease or harboring a pathogen. The sample can be mammalian-derived.

[0064] As used herein, the term "electrowetting" generally refers to any liquid handling technology that uses a voltage applied to an electrode or other conductor to move a fluid on a surface. The surface tension and wetting properties of the fluid can be altered by an electric field using the electrowetting effect. The electrowetting effect can result from a change in the solid-liquid contact angle due to an applied potential difference between the solid and the liquid. When the fluid is provided as a droplet, the difference in wetting surface tension can vary across the width of the droplet, and the corresponding change in the contact angle can provide a motive force to move the droplet without moving the component or making physical contact.

[0065] As used herein, the term "smooth surface" generally refers to a non-porous surface that is not patterned to improve the hydrophobicity of the surface. At least one 100 μm 2 portion of the surface is intended to contact the manipulated fluid, and if any 20 μm 2 portion has a roughness average ("Ra") of less than 10 μm and a Wenzel roughness factor of less than 2, the fluid manipulating surface is smooth, where the Wenzel roughness factor is defined as the ratio of the actual surface area of the surface to the projected surface area of the surface. Folds, wrinkles, and other surface defects do not prevent the film from being considered smooth by this definition.

[0066] The section headings used herein are for organizational purposes only and should not be construed as limiting the subject matter described.

[0067] Surface coating for contacting a fluid In one aspect, the present disclosure provides a surface coating for contacting a fluid. In some embodiments, contacting the fluid includes manipulating the fluid. In some embodiments, manipulating the fluid includes performing one or more operations such as moving the fluid on a surface.

[0068] In some embodiments, the surface coating is multilayer. In some embodiments, the surface coating has two layers. In some embodiments, the surface coating has three layers. In some embodiments, the surface coating has four layers. In some embodiments, the surface coating has five layers. In some embodiments, the surface coating has six layers. In some embodiments, the surface coating has seven layers. In some embodiments, the surface coating has eight layers. In some embodiments, the surface coating has nine layers. In some embodiments, each layer serves a different purpose and can improve fluid handling performance, such as electro-wetting performance, in a plurality of ways.

[0069] In some embodiments, the layer can include a surface-modified secondary coating, a film, an adhesive, a fluid, a vacuum, or a combination thereof.

[0070] In some embodiments, the surface coating includes a film layer and a liquid layer. FIG. 2 shows an exchangeable surface coating for fluid manipulation. As shown in FIG. 2, the exchangeable surface coating can include a smoothly coated film layer and a lubricating liquid layer that are differently coated.

[0071] In some embodiments, the film layer has a thickness of from about 0.1 micrometers (“μm”) to about 1000 μm. In some embodiments, the film layer has a thickness of at least about 0.1 μm, 0.2 μm, 0.3 μm, 0.4 μm, 0.5 μm, 0.6 μm, 0.7 μm, 0.8 μm, 0.9 μm, 1 μm, 2 μm, 3 μm, 4 μm, 5 μm, 6 μm, 7 μm, 8 μm, 9 μm, 10 μm, 20 μm, 30 μm, 40 μm, 50 μm, 60 μm, 70 μm, 80 μm, 90 μm, 100 μm, 200 μm, 300 μm, 400 μm, 500 μm, 600 μm, 700 μm, 800 μm, 900 μm, 1000 μm, or any value therebetween. In some embodiments, the film layer has a thickness of at most about 1000 μm, 900 μm, 800 μm, 700 μm, 600 μm, 500 μm, 400 μm, 300 μm, 200 μm, 100 μm, 90 μm, 80 μm, 70 μm, 60 μm, 50 μm, 40 μm, 30 μm, 20 μm, 10 μm, 9 μm, 8 μm, 7 μm, 6 μm, 5 μm, 4 μm, 3 μm, 2 μm, 1 μm, 0.9 μm, 0.8 μm, 0.7 μm, 0.6 μm, 0.5 μm, 0.4 μm, 0.3 μm, 0.2 μm, 0.1 μm, or any value therebetween.

[0072] Ra, or arithmetic mean height, can be a measure of surface roughness. Ra can be determined by averaging the absolute value of the deviation of the profile height from the mean line recorded over the evaluation area. In some embodiments, Ra is the arithmetic mean of the absolute value of the deviation of the profile height from the mean line of a particular surface measured by a profilometer. Ra values can be expressed, for example, in μm. The higher the Ra value, the rougher the surface. For example, in some cases, a surface with an Ra value of 0.1 μm is considered smooth, and a surface with an Ra value of 1 μm can be considered rough. Other measures of surface roughness that can be appropriate in some embodiments are root mean square (e.g., calculated by taking the square root of the arithmetic mean of the deviation of the profile height from the mean line), mean line averaging (e.g., calculated by averaging the absolute value of the deviation of the profile height from the mean line regardless of sign), or total height (e.g., calculated as the difference between the highest peak and the deepest valley over the evaluation length).

[0073] In some embodiments, the film layer may not be textured. In some embodiments, not being textured may refer to a surface that is completely smooth (e.g., has no variation in profile height). In some embodiments, not being textured may refer to a surface having a slight deviation in profile height or a deviation within an acceptable or predetermined range. For example, the Ra of a non-textured film layer can be from about 100 nm to about 0 nm. In some embodiments, the Ra of a non-textured film layer can be from about 100 μm to about 0 μm. In some embodiments, a non-textured film layer has an Ra of at least about 0 μm, 0.01 μm, 0.02 μm, 0.03 μm, 0.04 μm, 0.05 μm, 0.06 μm, 0.07 μm, 0.08 μm, 0.09 μm, 0.1 μm, 0.2 μm, 0.3 μm, 0.4 μm, 0.5 μm, 0.6 μm, 0.7 μm, 0.8 μm, 0.9 μm, 1 μm, 2 μm, 3 μm, 4 μm, 5 μm, 6 μm, 7 μm, 8 μm, 9 μm, 10 μm, 20 μm, 30 μm, 40 μm, 50 μm, 60 μm, 70 μm, 80 μm, 90 μm, 100 μm, or any value therebetween. In some embodiments, a non-textured film layer has an Ra of at most about μm, 90 μm, 80 μm, 70 μm, 60 μm, 50 μm, 40 μm, 30 μm, 20 μm, 10 μm, 9 μm, 8 μm, 7 μm, 6 μm, 5 μm, 4 μm, 3 μm, 2 μm, 1 μm, 0.9 μm, 0.8 μm, 0.7 μm, 0.6 μm, 0.5 μm, 0.4 μm, 0.3 μm, 0.2 μm, 0.1 μm, 0.09 μm, 0.08 μm, 0.07 μm, 0.06 μm, 0.05 μm, 0.04 μm, 0.03 μm, 0.02 μm, 0.01 μm, 0 μm, or any value therebetween.

[0074] In some embodiments, the present disclosure includes a low surface energy oil formed via a slippery liquid coating and liquid-on-liquid electrowetting (LLEW). A thin film of the oil can be formed on a low surface energy textured or untextured solid surface. The solid (e.g., a dielectric film) and the lubricating oil can be selected such that the lubricating oil preferentially wets the solid. In some embodiments, the solid (e.g., a dielectric film) and the lubricating oil can be selected such that the lubricating oil completely wets the solid and does not interact with a liquid (e.g., a droplet or body fluid if the surface is used to coat an implant). When most of the solid is covered with oil, additional oil can be added on top of the solid. The self-leveling nature of the upper oil layer can hide any non-uniformities in the topography of the underlying surface of the support structure. Thus, the surface of an electrode array having a very high roughness (tens of micrometers) can be converted into a nearly molecularly smooth surface having a thin layer of lubricating oil. This molecularly smooth surface provides little or no friction to the movement of droplets, and the droplets may hardly be pinned. Droplets on such a smooth surface can have a very small contact angle hysteresis (as low as about 2°). The resulting low contact angle hysteresis and the absence of droplet pinning can result in a very low operating voltage (1 V to 100 V) with robust droplet manipulation. The oil on top of the solid can be trapped on top of the solid by the wetting interaction between the oil and the solid. The oil layer can have sufficient affinity and molecular interaction with the surface of the solid to mitigate the effects of gravity. Since the oil may not leave the surface of the solid, a droplet or body fluid that interacts with the solid can ride on the lubricating oil, interact with the surface of the lubricating oil, and not interact with the solid of the support structure. As a result, the droplet or body fluid may leave little or no trace on the solid of the support structure.When the oil is immiscible with the droplets or body fluids, the droplets or body fluids can move over the liquid layer without any contamination between two consecutive droplets crossing the path or between different body fluids. The lubricating oil can be any low-energy oil such as silicone oil, DuPont Krytox oil, Fluorinert FC-70, or other oils. The lubricating oil can be selected such that the oil is immiscible with the droplets or body fluids. A lubricant that is immiscible with the droplet solvent can suppress the diffusion of oil from the droplets and the contents of the droplets from the oil, and can improve the ability of the droplets to ride over the lubricant or oil. The viscosity of the lubricating oil can affect the droplet mobility during electro-wetting, and a lower viscosity results in higher mobility. The appropriate lubricating oil can be non-volatile and immiscible with the targeted ridden droplets. When the droplets contain biological constructs, a biocompatible oil may be desirable. In an LLEW device having an on-chip heating element for incubation and thermal cycling (e.g., for polymerase chain reaction), the oil can be selected to withstand heating and high temperatures. An oil having a sufficiently high dielectric constant can reduce the operating voltage that induces the movement of the droplets.

[0075] In LLEW, a solid containing an oil layer thereon can function as an electrical barrier between the electrode array and / or underlying electro-mechanics and a droplet or body fluid. This can also provide a slippery surface for the movement of droplets and an improved interaction with body fluids. There are several different ways in which the described system can be created. The solid surface can be formed on the electrode array by bonding a polymer or other dielectric material as a film. If desired, a non-textured film can be adhered onto the electrode array and then textured, for example, by any of laser etching, chemical etching, or photolithography techniques. A layer of photosensitive material such as photoresist (SU-8) can be coated onto the electrode array. The textured solid layer can be covered with a lubricating oil by spin coating, spraying, dip coating, brushing, drop coating, or by supplying from a reservoir. The lubricating oil can be kept from flowing out from the surface of the solid (e.g., LLEW) chip by forming a physical or chemical barrier around the device. The surface of the solid has two unique properties desirable for the manipulation of biological samples or for bioprostheses. On an electrowetting surface, since the LLEW array has such a smooth surface, the operating voltage can be significantly reduced. Furthermore, the LLEW surface architecture can reduce cross-contamination between samples by not only reducing the traces left by droplets but also improving the cleaning mechanism. The near molecular-level smoothness of the surface of the oil on the LLEW electrode array can reduce or eliminate droplet pinning. Droplets made of an aqueous solution riding on the surface of the oil experience little or no drag force from the surface, and thus the difference between the advancing angle and the receding angle can be small, which feature is particularly useful in embodiments where the lubricating oil is applied to the surface of a bioprosthesis. The elimination of these two phenomena can result in a low operating voltage. Droplets can be operated at a voltage as low as about 1V. In the LLEW device, droplets riding on a thin layer of oil may never physically contact the solid dielectric substrate under the oil, which is also particularly useful in embodiments where the oil is applied to the surface of a bioprosthesis.This can reduce or eliminate the amount of remaining material and thus reduce or eliminate cross - contamination between samples that interact with the same spot.

[0076] When the LLEW device is contaminated with solid particles such as dust, the droplets can be manipulated over the contaminants in order to remove the contaminants from the liquid - film surface as part of a cleaning routine. This cleaning routine can be further extended to clean the entire surface of the electro - wetting device. For example, the cleaning routine can be used between two biological experiments on the LLEW microfluidic chip in order to reduce cross - contamination. In some cases, when a droplet remains in a position for a long period of time, a small number of molecules can diffuse from the droplet into the underlying oil. Through diffusion, any residue left by the droplet can also be cleaned with a similar cleaning routine. The droplets are transported on the LLEW device and the droplets can carry and deplete the oil film from the surface. The oil on the surface can be replenished by injecting oil from an external reservoir, for example, an inkjet cartridge, a syringe pump, or other dispensing mechanisms. Flushing the surface of the lubricating oil completely and replacing it with a new layer of oil can prevent cross - contamination between two consecutive experiments.

[0077] As described above, a particular advantage of the present disclosure is a reduction in the operating voltage sufficient to perform droplet manipulation on the surface described herein. In some embodiments, the operating voltage is from about 1V to about 10V. In some embodiments, the operating voltage is from about 1V to about 2V, from about 1V to about 3V, from about 1V to about 4V, from about 1V to about 5V, from about 1V to about 6V, from about 1V to about 7V, from about 1V to about 8V, from about 1V to about 9V, from about 1V to about 10V, from about 2V to about 3V, from about 2V to about 4V, from about 2V to about 5V, from about 2V to about 6V, from about 2V to about 7V, from about 2V to about 8V, from about 2V to about 9V, from about 2V to about 10V, from about 3V to about 4V, from about 3V to about 5V, from about 3V to about 6V, from about 3V to about 7V, from about 3V to about 8V, from about 3V to about 9V, from about 3V to about 10V, from about 4V to about 5V, from about 4V to about 6V, from about 4V to about 7V, from about 4V to about 8V, from about 4V to about 9V, from about 4V to about 10V, from about 5V to about 6V, from about 5V to about 7V, from about 5V to about 8V, from about 5V to about 9V, from about 5V to about 10V, from about 6V to about 7V, from about 6V to about 8V, from about 6V to about 9V, from about 6V to about 10V, from about 7V to about 8V, from about 7V to about 9V, from about 7V to about 10V, from about 8V to about 9V, from about 8V to about 10V, or from about 9V to about 10V. In some embodiments, the operating voltage is about 1V, about 2V, about 3V, about 4V, about 5V, about 6V, about 7V, about 8V, about 9V, or about 10V. In some embodiments, the operating voltage is at least about 1V, about 2V, about 3V, about 4V, about 5V, about 6V, about 7V, about 8V, or about 9V. In some embodiments, the operating voltage is at most about 2V, about 3V, about 4V, about 5V, about 6V, about 7V, about 8V, about 9V, or about 10V. In some embodiments, the operating voltage is from about 10V to about 100V.In some embodiments, the operating voltage is from about 10V to about 20V, from about 10V to about 30V, from about 10V to about 40V, from about 10V to about 50V, from about 10V to about 60V, from about 10V to about 70V, from about 10V to about 80V, from about 10V to about 90V, from about 10V to about 100V, from about 20V to about 30V, from about 20V to about 40V, from about 20V to about 50V, from about 20V to about 60V, from about 20V to about 70V, from about 20V to about 80V, from about 20V to about 90V, from about 20V to about 100V, from about 30V to about 40V, from about 30V to about 50V, from about 30V to about 60V, from about 30V to about 70V, from about 30V to about 80V, from about 30V to about 90V, from about 30V to about 100V, from about 40V to about 50V, from about 40V to about 60V, from about 40V to about 70V, from about 40V to about 80V, from about 40V to about 90V, from about 40V to about 100V, from about 50V to about 60V, from about 50V to about 70V, from about 50V to about 80V, from about 50V to about 90V, from about 50V to about 100V, from about 60V to about 70V, from about 60V to about 80V, from about 60V to about 90V, from about 60V to about 100V, from about 70V to about 80V, from about 70V to about 90V, from about 70V to about 100V, from about 80V to about 90V, from about 80V to about 100V, or from about 90V to about 100V. In some embodiments, the operating voltage is about 10V, about 20V, about 30V, about 40V, about 50V, about 60V, about 70V, about 80V, about 90V, or about 100V. In some embodiments, the operating voltage is at least about 10V, about 20V, about 30V, about 40V, about 50V, about 60V, about 70V, about 80V, or about 90V. In some embodiments, the operating voltage is at most about 20V, about 30V, about 40V, about 50V, about 60V, about 70V, about 80V, about 90V, or about 100V. In some embodiments, the operating voltage is from about 125V to about 400V.In some embodiments, the operating voltage is from about 125V to about 150V, from about 125V to about 175V, from about 125V to about 200V, from about 125V to about 225V, from about 125V to about 250V, from about 125V to about 275V, from about 125V to about 300V, from about 125V to about 325V, from about 125V to about 350V, from about 125V to about 375V, from about 125V to about 400V, from about 150V to about 175V, from about 150V to about 200V, from about 150V to about 225V, from about 150V to about 250V, from about 150V to about 275V, from about 150V to about 300V, from about 150V to about 325V, from about 150V to about 350V, from about 150V to about 375V, from about 150V to about 400V, from about 175V to about 200V, from about 175V to about 225V, from about 175V to about 250V, from about 175V to about 275V, from about 175V to about 300V, from about 175V to about 325V, from about 175V to about 350V, from about 175V to about 375V, from about 175V to about 400V, from about 200V to about 225V, from about 200V to about 250V, from about 200V to about 275V, from about 200V to about 300V, from about 200V to about 325V, from about 200V to about 350V, from about 200V to about 375V, from about 200V to about 400V, from about 225V to about 250V, from about 225V to about 275V, from about 225V to about 300V, from about 225V to about 325V, from about 225V to about 350V, from about 225V to about 375V, from about 225V to about 400V, from about 250V to about 275V, from about 250V to about 300V, from about 250V to about 325V, from about 250V to about 350V, from about 250V to about 375V, from about 250V to about 400V, from about 275V to about 300V, from about 275V to about 325V, from about 275V to about 350V, from about 275V to about 375V, from about 275V to about 400V, from about 300V to about 325V, from about 300V to about 350V, from about 300V to about 375V, from about 300V to about 400V, from about 325V to about 350V, from about 325V to about 375V, from about 325V to about 400V, from about 350V to about 375V, from about 350V to about 400V, or from about 375V to about 400V. In some embodiments, the operating voltage is about 125V, about 150V, about 175V, about 200V, about 225V, about 250V, about 275V, about 300V, about 325V, about 350V, about 375V, or about 400V.In some embodiments, the operating voltage is at least about 125V, about 150V, about 175V, about 200V, about 225V, about 250V, about 275V, about 300V, about 325V, about 350V, or about 375V. In some embodiments, the operating voltage is at most about 150V, about 175V, about 200V, about 225V, about 250V, about 275V, about 300V, about 325V, about 350V, about 375V, or about 400V.

[0078] In some embodiments, the film layer comprises one or more polymer films, inorganic films, composite films, or combinations thereof. In some embodiments, the film layer is a composite film layer in which two or more films are laminated. In some embodiments, the film layer is a composite film layer in which three or more films are laminated. In some embodiments, the film layer is a composite film layer in which four or more films are laminated. In some embodiments, the film layer is a composite film layer in which five or more films are laminated. The composite film utilizes the various properties of each material used.

[0079] In some embodiments, the film layer may comprise an insulating dielectric material. In some embodiments, the film layer comprises polyethylene, polypropylene, polystyrene, polyether ether ketone (PEEK), polyimide, polyacetal, polysulfone, polyphenylene ether, polyphenylene sulfide (PPS), polyvinyl chloride, synthetic rubber, natural rubber, neoprene, nylon, polyacrylonitrile, polyvinyl butyral, silicone, parafilm, polyethylene terephthalate, polybutylene terephthalate, polyamide, polyoxymethylene, polycarbonate, polymethylpentene, polyphenylene oxide (polyphenylene ether), polyphthalamide (PPA), polylactic acid, synthetic cellulose ether (e.g., methylcellulose, ethylcellulose, propylcellulose, hydroxyethylcellulose, hydroxyethylcellulose, hydroxypropylcellulose (HPC), hydroxyethylmethylcellulose, hydroxypropylmethylcellulose (HPMC), ethylhydroxyethylcellulose), paraffin, microcrystalline wax, epoxy, polytetrafluoroethylene (PTFE), tetrafluoroethylene (TFE), fluorinated ethylene propylene copolymer (FEP), polyvinylidene fluoride (PVDF), perfluoroalkoxy tetrafluoroethylene copolymer (PFA), perfluoromethyl vinyl ether copolymer (MFA), ethylene chlorotrifluoroethylene copolymer (ECTFE), ethylene-tetrafluoroethylene copolymer (ETFE), perfluoropolyether (PFPE), polychlorotetrafluoroethylene (PCTFE), ceramic, borosilicate glass, quartz, alumina, silica, clay mineral, bentonite, kaolinite, vermiculite, graphite, molybdenum disulfide, mica, boron nitride, sodium formate, sodium oleate, sodium palmitate, sodium sulfate, sodium alginate, other polymeric materials, other ceramic materials, or combinations thereof.

[0080] In some embodiments, the film layer can be modified. In some embodiments, the film layer can be modified by applying a secondary coating to the film layer or by functionalizing the surface of the film layer. Either the secondary coating or the surface functionalization can be selected to improve the affinity of the film layer for the liquid layer. The modification of the film layer can be achieved in either the liquid phase or the gas phase. The film layer can be modified on either side, and both sides of the film layer can include the same or different modifications. The film layer can be modified to improve hydrophobicity and fluid handling.

[0081] In some embodiments, the modification can be selected to improve other properties such as durability, breakdown voltage, electrical resistivity, dielectric constant, environmental impact, elasticity, coefficient of thermal expansion, thermal conductivity, or combinations thereof.

[0082] In some embodiments, the liquid layer can diffuse into the film layer and swell the film layer. FIGS. 3A-3D are diagrams showing the swelling of the film layer by the liquid layer. Since the film layer is smooth, the liquid layer does not fill any surface.

[0083] In some embodiments, the liquid layer is non-uniform. In some embodiments, the liquid layer has an average initial thickness of from about 0.1 μm to about 500 μm. In some embodiments, the liquid layer has a thickness of at least about 0.1 μm, 0.2 μm, 0.3 μm, 0.4 μm, 0.5 μm, 0.6 μm, 0.7 μm, 0.8 μm, 0.9 μm, 1 μm, 2 μm, 3 μm, 4 μm, 5 μm, 6 μm, 7 μm, 8 μm, 9 μm, 10 μm, 20 μm, 30 μm, 40 μm, 50 μm, 60 μm, 70 μm, 80 μm, 90 μm, 100 μm, 200 μm, 300 μm, 400 μm, 500 μm, or any value therebetween. In some embodiments, the liquid layer has a maximum thickness of about 500 μm, 400 μm, 300 μm, 200 μm, 100 μm, 90 μm, 80 μm, 70 μm, 60 μm, 50 μm, 40 μm, 30 μm, 20 μm, 10 μm, 9 μm, 8 μm, 7 μm, 6 μm, 5 μm, 4 μm, 3 μm, 2 μm, 1 μm, 0.9 μm, 0.8 μm, 0.7 μm, 0.6 μm, 0.5 μm, 0.4 μm, 0.3 μm, 0.2 μm, 0.1 μm, or any value therebetween. In some embodiments, the liquid layer has a maximum thickness of about 0.1 centimeter (cm), 0.2 cm, 0.3 cm, 0.4 cm, 0.5 cm, 0.6 cm, 0.7 cm, 0.8 cm, 0.9 cm, 1.0 cm, 1.1 cm, 1.2 cm, 1.3 cm, 1.4 cm, 1.5 cm, 1.6 cm, 1.7 cm, 1.8 cm, 1.9 cm, or 2.0 cm. In embodiments where the liquid layer is non-uniform, the liquid layer can have a minimum thickness (e.g., initially, after a period of time, under a droplet, etc.) of about 1 nanometer (nm), 2 nm, 3 nm, 4 nm, 5 nm, 6 nm, 7 nm, 8 nm, 9 nm, 10 nm, 20 nm, 30 nm, 40 nm, 50 nm, 60 nm, 70 nm, 80 nm, 90 nm, 100 nm, 200 nm, 300 nm, 400 nm, 500 nm, 600 nm, 700 nm, 800 nm, 900 nm, 1000 nm, 2000 nm, 3000 nm, 4000 nm, 5000 nm, 6000 nm, 7000 nm, 8000 nm, 9000 nm, 10000 nm, etc. In some embodiments, the thickness of the liquid layer can decrease over time after the application of the liquid layer.In some embodiments, the thickness of the liquid layer can decrease (e.g., locally) under the weight of the droplets on the liquid layer.

[0084] The viscosity of the liquid layer can be selected to optimize the fluidity of the liquid layer, reduce drag, and enhance durability. In some embodiments, the liquid layer has a viscosity of from about 0.5 centistokes (cSt) to about 100 cSt. In some embodiments, the liquid layer has a viscosity of from about 0 cSt to about 20 cSt. In some embodiments, the liquid layer has a viscosity of from about 0 cSt to about 30 cSt. In some embodiments, the liquid layer has a viscosity of from about 5 cSt to about 20 cSt. In some embodiments, the liquid layer has a viscosity of at least about 0 cSt, 0.1 cSt, 0.2 cSt, 0.3 cSt, 0.4 cSt, 0.5 cSt, 0.6 cSt, 0.7 cSt, 0.8 cSt, 0.9 cSt, 1 cSt, 2 cSt, 3 cSt, 4 cSt, 5 cSt, 6 cSt, 7 cSt, 8 cSt, 9 cSt, 10 cSt to 20 cSt, 30 cSt, 40 cSt, 50 cSt, 60 cSt, 70 cSt, 80 cSt, 90 cSt, 100 cSt, or any value therebetween. In some embodiments, the liquid layer has a viscosity of at most about 100 cSt, 90 cSt, 80 cSt, 70 cSt, 60 cSt, 50 cSt, 40 cSt, 30 cSt, 20 cSt, 10 cSt, 9 cSt, 8 cSt, 7 cSt, 6 cSt, 5 cSt, 4 cSt, 3 cSt, 2 cSt, 1 cSt, 0.9 cSt, 0.8 cSt, 0.7 cSt, 0.6 cSt, 0.5 sCt, or any value therebetween. The values provided herein for the viscosity of the liquid layer can be measured when the liquid layer is at room temperature.

[0085] In some embodiments, the liquid layer has a viscosity of from about 0 cST to about 5 cST. In some embodiments, the liquid layer has a viscosity of from about 0 cST to about 0.5 cST, from about 0 cST to about 1 cST, from about 0 cST to about 1.5 cST, from about 0 cST to about 2 cST, from about 0 cST to about 2.5 cST, from about 0 cST to about 3 cST, from about 0 cST to about 3.5 cST, from about 0 cST to about 4 cST, from about 0 cST to about 4.5 cST, from about 0 cST to about 5 cST, from about 0.5 cST to about 1 cST, from about 0.5 cST to about 1.5 cST, from about 0.5 cST to about 2 cST, from about 0.5 cST to about 2.5 cST, from about 0.5 cST to about 3 cST, from about 0.5 cST to about 3.5 cST, from about 0.5 cST to about 4 cST, from about 0.5 cST to about 4.5 cST, from about 0.5 cST to about 5 cST, from about 1 cST to about 1.5 cST, from about 1 cST to about 2 cST, from about 1 cST to about 2.5 cST, from about 1 cST to about 3 cST, from about 1 cST to about 3.5 cST, from about 1 cST to about 4 cST, from about 1 cST to about 4.5 cST, from about 1 cST to about 5 cST, from about 1.5 cST to about 2 cST, from about 1.5 cST to about 2.5 cST, from about 1.5 cST to about 3 cST, from about 1.5 cST to about 3.5 cST, from about 1.5 cST to about 4 cST, from about 1.5 cST to about 4.5 cST, from about 1.5 cST to about 5 cST, from about 2 cST to about 2.5 cST, from about 2 cST to about 3 cST, from about 2 cST to about 3.5 cST, from about 2 cST to about 4 cST, from about 2 cST to about 4.5 cST, from about 2 cST to about 5 cST, from about 2.5 cST to about 3 cST, from about 2.5 cST to about 3.5 cST, from about 2.5 cST to about 4 cST, from about 2.5 cST to about 4.5 cST, from about 2.5 cST to about 5 cST, from about 3 cST to about 3.5 cST, from about 3 cST to about 4 cST, from about 3 cST to about 4.5 cST, from about 3 cST to about 5 cST, from about 3.5 cST to about 4 cST, from about 3.5 cST to about 4.5 cST, from about 3.5 cST to about 5 cST, from about 4 cST to about 4.5 cST, from about 4 cST to about 5 cST, or from about 4.5 cST to about 5 cST. In some embodiments, the liquid layer has a viscosity of about 0 cST, about 0.5 cST, about 1 cST, about 1.5 cST, about 2 cST, about 2.5 cST, about 3 cST, about 3.5 cST, about 4 cST, about 4.5 cST, or about 5 cST.In some embodiments, the liquid layer has a viscosity of at least about 0 cST, about 0.5 cST, about 1 cST, about 1.5 cST, about 2 cST, about 2.5 cST, about 3 cST, about 3.5 cST, about 4 cST, or about 4.5 cST. In some embodiments, the liquid layer has a viscosity of at most about 0.5 cST, about 1 cST, about 1.5 cST, about 2 cST, about 2.5 cST, about 3 cST, about 3.5 cST, about 4 cST, about 4.5 cST, or about 5 cST. In some embodiments, the liquid layer has a viscosity of from about 5 cST to about 20 cST. In some embodiments, the liquid layer has a viscosity of from about 5 cST to about 7.5 cST, from about 5 cST to about 10 cST, from about 5 cST to about 12.5 cST, from about 5 cST to about 15 cST, from about 5 cST to about 17.5 cST, from about 5 cST to about 20 cST, from about 7.5 cST to about 10 cST, from about 7.5 cST to about 12.5 cST, from about 7.5 cST to about 15 cST, from about 7.5 cST to about 17.5 cST, from about 7.5 cST to about 20 cST, from about 10 cST to about 12.5 cST, from about 10 cST to about 15 cST, from about 10 cST to about 17.5 cST, from about 10 cST to about 20 cST, from about 12.5 cST to about 15 cST, from about 12.5 cST to about 17.5 cST, from about 12.5 cST to about 20 cST, from about 15 cST to about 17.5 cST, from about 15 cST to about 20 cST, or from about 17.5 cST to about 20 cST. In some embodiments, the liquid layer has a viscosity of about 5 cST, about 7.5 cST, about 10 cST, about 12.5 cST, about 15 cST, about 17.5 cST, or about 20 cST. In some embodiments, the liquid layer has a viscosity of at least about 5 cST, about 7.5 cST, about 10 cST, about 12.5 cST, about 15 cST, or about 17.5 cST. In some embodiments, the liquid layer has a viscosity of at most about 7.5 cST, about 10 cST, about 12.5 cST, about 15 cST, about 17.5 cST, or about 20 cST. In some embodiments, the liquid layer has a viscosity of from about 20 cST to about 100 cST.In some embodiments, the liquid layer has a viscosity of about 20 cST to about 30 cST, about 20 cST to about 40 cST, about 20 cST to about 50 cST, about 20 cST to about 60 cST, about 20 cST to about 70 cST, about 20 cST to about 80 cST, about 20 cST to about 90 cST, about 20 cST to about 100 cST, about 30 cST to about 40 cST, about 30 cST to about 50 cST, about 30 cST to about 60 cST, about 30 cST to about 70 cST, about 30 cST to about 80 cST, about 30 cST to about 90 cST, about 30 cST to about 100 cST, about 40 cST to about 50 cST, about 40 cST to about 60 cST, about 40 cST to about 70 cST, about 40 cST to about 80 cST, about 40 cST to about 90 cST, about 40 cST to about 100 cST, about 50 cST to about 60 cST, about 50 cST to about 70 cST, about 50 cST to about 80 cST, about 50 cST to about 90 cST, about 50 cST to about 100 cST, about 60 cST to about 70 cST, about 60 cST to about 80 cST, about 60 cST to about 90 cST, about 60 cST to about 100 cST, about 70 cST to about 80 cST, about 70 cST to about 90 cST, about 70 cST to about 100 cST, about 80 cST to about 90 cST, about 80 cST to about 100 cST, or about 90 cST to about 100 cST. In some embodiments, the liquid layer has a viscosity of about 20 cST, about 30 cST, about 40 cST, about 50 cST, about 60 cST, about 70 cST, about 80 cST, about 90 cST, or about 100 cST. In some embodiments, the liquid layer has a viscosity of at least about 20 cST, about 30 cST, about 40 cST, about 50 cST, about 60 cST, about 70 cST, about 80 cST, or about 90 cST. In some embodiments, the liquid layer has a viscosity of at most about 30 cST, about 40 cST, about 50 cST, about 60 cST, about 70 cST, about 80 cST, about 90 cST, or about 100 cST. The values provided herein for the viscosity of the liquid layer can be measured when the liquid layer is at room temperature.

[0086] In some embodiments, the liquid layer has a static contact angle with the film layer of about 10 degrees or less. The small static contact angle helps to improve lubricity and reduce fouling and pinning during fluid operation. In some embodiments, the liquid layer has a static contact angle with the film layer of at least about 0.1 degrees, 0.2 degrees, 0.3 degrees, 0.4 degrees, 0.5 degrees, 0.6 degrees, 0.7 degrees, 0.8 degrees, 0.9 degrees, 1 degree, 2 degrees, 3 degrees, 4 degrees, 5 degrees, 6 degrees, 7 degrees, 8 degrees, 9 degrees, 10 degrees, or any value in between. In some embodiments, the liquid layer has a static contact angle with the film layer of up to about 10 degrees, 9 degrees, 8 degrees, 7 degrees, 6 degrees, 5 degrees, 4 degrees, 3 degrees, 2 degrees, 1 degree, 0.9 degrees, 0.8 degrees, 0.7 degrees, 0.6 degrees, 0.5 degrees, 0.4 degrees, 0.3 degrees, 0.2 degrees, 0.1 degrees, or any value in between.

[0087] In some embodiments, the liquid layer is a lubricating layer. The lubricating layer improves the overall fluid mobility by reducing the friction between the film layer and the droplets, preventing droplet pinning, reducing fouling, and reducing contact angle hysteresis. Good fluid mobility can be defined by the ability to move a fluid accurately, reliably, at high speed, over a long period of time, or without pinning and fouling on the surface.

[0088] In some embodiments, the lubricating layer is selected for its affinity for the film layer and immiscibility with the fluid being operated on. The affinity of the liquid layer for the film layer prevents the liquid layer from being displaced by the fluid being operated on. Since the lubricating layer is selected for its affinity for the film layer, the surface coating is easy to manufacture. For example, hydrocarbon fluids can be used with polyolefin films, silicone fluids can be used with silicone films, and fluorinated fluids can be used with fluorinated polymer films.

[0089] In some embodiments, the lubricating layer is a hydrocarbon layer, a silicone layer, a fluorinated layer, or a combination thereof.

[0090] In some embodiments, the lubricating layer includes polydimethylsiloxane, polymethylhydrogen siloxane / hydrogen silicone oil, aminosilicone oil, phenylmethyl silicone oil, diphenyl silicone oil, vinyl silicone oil, hydroxysilicone oil, cyclopolysiloxane, polyalkylene oxide silicone, silicone resin, perfluoropolyether (PFPE), perfluoroalkane, fluorinated ionic fluid, fluorinated silicone oil, perfluoroalkyl ether, perfluorotri-n-butylamine (FC-40), hydrofluoroether (HFE) liquid, ionic liquid, mineral oil, ferromagnetic fluid, polyphenyl ether, vegetable oil, esters of saturated fatty acids and dibasic acids, grease, fatty acid, triglyceride, polyalphaolefin, polyglycol hydrocarbon, other alkanes, other non-hydrocarbon synthetic oils, or combinations thereof.

[0091] In some embodiments, the lubricating layer may include additives. In some embodiments, the additives are rheology modifiers, fillers, solvents, surfactants, dyes, or combinations thereof. Rheology modifiers, fillers, and solvents can help adjust the viscosity of the liquid and can impart non-Newtonian flow properties to the liquid. Fillers can help improve material properties such as thermal conductivity and dielectric constant and can also change rheological properties. Surfactants and solvents can help adjust the surface energy of the lubricating layer between the film layer and the fluid being operated on.

[0092] In some embodiments, some or all of the surface coating can be removed and replaced. In some embodiments, the surface coating can be used once. In some embodiments, the surface coating can be used multiple times. In some embodiments, the coating can be permanent. FIG. 4 is a diagram showing a permanent surface coating for fluid operation according to some embodiments.

[0093] In some embodiments, the coatings described herein can be applied to surfaces intended to contact fluids. In some embodiments, non-limiting examples of surfaces intended to contact fluids include cannulas, connectors, catheters (e.g., central line, peripherally inserted central catheter (PICC) line, urinary, vascular, peritoneal dialysis, and central venous catheters), catheter connectors (e.g., Leur-Lok and needleless connectors), clamps, skin hooks, cuffs, retractors, shunts, needles, capillaries, endotracheal tubes, ventilators, associated ventilator tubes, drug delivery media, syringes, microscope slides, plates, films, laboratory work surfaces, wells, well plates, Petri dishes, tiles, jars, flasks, beakers, vials, test tubes, tube connectors, columns, containers, cuvettes, bottles, drums, baths, tanks, organs, organ implants, or organ components (e.g., intrauterine contraceptive devices, defibrillators, corneas, breasts, artificial knee joints, and artificial hip implants), artificial organs or their components (e.g., heart valves, ventricular assist devices, total artificial hearts, cochlear implants, visual prostheses, and their components), dental tools, dental implants (e.g., root form, plate form, and subperiosteal implants), biosensors (e.g., glucose and insulin monitors, blood oxygen sensors, hemoglobin sensors, bioelectromechanical devices (bioMEMs), sepsis diagnostic sensors, and other protein and enzyme sensors), bioelectrodes, endoscopes (hysteroscopes, cystoscopes, amnioscopes, laparoscopes, gastroscopes, enteroscopes, bronchoscopes, esophagoscopes, nasal scopes, arthroscopes, proctoscopes, colonoscopes, nephroscopes, angioscopes, thoracoscopes, esophagoscopes, laryngoscopes, and brain scopes), wound dressings (e.g., bandages, sutures, staples), flow cells, microfluidic devices, and combinations thereof.

[0094] In some embodiments, the coatings described herein may be applied to devices such as research arrays and diagnostic arrays. Examples of research arrays and diagnostic arrays may include sample preparation, amplification, rolling circle amplification, bridge amplification, sequencing, circular consensus sequencing, next-generation sequencing, polymerase chain reaction, enzymatic polymer synthesis, and sample detection arrays.

[0095] Fluid handling device In another aspect, the present disclosure provides an apparatus for fluid handling that includes the surface coating described herein. In some embodiments, the apparatus can be an electrowetting microfluidic device.

[0096] In some embodiments, the apparatus includes a substrate having one or more electrodes and a first surface that includes the coating described herein. In some embodiments, the first surface includes a film layer and a liquid layer.

[0097] In some embodiments, the electrodes consist of conductive plates that are electrically charged to actuate the fluid. In some embodiments, the electrodes can be arranged in any layout, for example, as a rectangular grid or as a collection of discrete paths. In some embodiments, the shape of the electrodes is arbitrary.

[0098] In some embodiments, the electrode includes a conductive metal, a conductive oxide, a semiconductor, a conductive polymer, or a combination thereof. In some embodiments, the electrode is made of a conductive metal selected from gold, silver, copper, nickel, aluminum, platinum, titanium, or a combination thereof. In some embodiments, the electrode includes a conductive oxide selected from indium tin oxide, aluminum doped zinc oxide, and combinations thereof. In some embodiments, the electrode includes a semiconductor such as silicon dioxide. Since the electrode is conductive, a first surface including an insulator or a dielectric is used to separate the electrode and the manipulated fluid to prevent oxidation and reduction reactions on the electrode and the manipulated fluid. In some embodiments, the dielectric can be up to about 1 millimeter (mm). For example, the dielectric can be up to about 0.001 mm, 0.002 mm, 0.003 mm, 0.004 mm, 0.005 mm, 0.006 mm, 0.007 mm, 0.008 mm, 0.009 mm, 0.01 mm, 0.02 mm, 0.03 mm, 0.04 mm, 0.05 mm, 0.06 mm, 0.07 mm, 0.08 mm, 0.09 mm, 0.1 mm, 0.2 mm, 0.3 mm, 0.4 mm, 0.5 mm, 0.6 mm, 0.7 mm, 0.8 mm, 0.9 mm, or 1 mm. In some embodiments, the dielectric can be up to about 2 mm, 3 mm, 4 mm, 5 mm, 6 mm, 7 mm, 8 mm, 9 mm, or 10 mm.

[0099] In some embodiments, the substrate supporting the electrode can include any insulating material of any thickness and rigidity.

[0100] In some embodiments, the electrode is fabricated on a standard rigid and flexible printed circuit board ("PCB") substrate. In some embodiments, the substrate for the PCB is FR4 (glass - epoxy), FR2 (glass - epoxy) or an insulated metal substrate (IMS), a polyimide film (e.g., commercially available products including Kapton, Pyralux), polyethylene terephthalate (PET), ceramic, or other commercially available substrates.

[0101] In some embodiments, the substrate further includes a sealant layer. In some embodiments, the sealant layer can act as an insulator, a moisture barrier, a corrosion barrier, or a reaction barrier. In some embodiments, the sealant layer includes a fluoropolymer, a polyurethane, an acrylic, a silicone, a polyolefin, a parylene, or a combination thereof.

[0102] In some embodiments, the electrodes are fabricated using thin-film transistor (TFT) technology. A TFT can be a type of field-effect transistor (FET) in which the transistors of the TFT are fabricated by thin film deposition. A TFT can be deployed on a supporting (but non-conductive) substrate (e.g., glass) different from a bulk metal-oxide semiconductor field-effect transistor (MOSFET), where the semiconductor material is typically a substrate (e.g., a silicon wafer).

[0103] As shown in FIGS. 5A - 5C, the first surface of the device can be flat, curved, tubular, horizontal, vertical, or any combination thereof. As shown in FIGS. 5A - 5C, the device can further include a second surface parallel to the first surface. In some embodiments, the second surface includes the surface coatings described herein. As shown in FIGS. 5A - 5C, the fluid being manipulated can be disposed between the first surface and the second surface. In some embodiments, the surface coatings can be used on the surfaces of other optical manipulation techniques such as optoelectrowetting devices or laser tweezers.

[0104] A printed circuit board (PCB) manufactured by a typical process has surface roughness in the form of, for example, cations (gaps) between electrodes, holes (also known as vias) for establishing connections between multiple layers, holes for soldering through-hole components, and any other defects due to manufacturing errors. Thus, a gap filling fluid may be used to smooth the surface of the PCB and to facilitate adhesion between the substrate and the first surface.

[0105] In some embodiments, the device further includes a gap filling fluid between the substrate and the first surface. The gap filling fluid serves to fill the void between the substrate and the first surface. FIGS. 6A and 6B are diagrams showing the relationship between the substrate, the capillary fluid, and the first surface.

[0106] In some embodiments, the gap filling fluid forms a displacement capacitance between the substrate and the first surface. In some embodiments, the displacement capacitance has an average height of at least about 0.01 μm, 0.02 μm, 0.03 μm, 0.04 μm, 0.05 μm, 0.06 μm, 0.07, 0.08 μm, 0.09 μm, 0.1 μm, 0.2 μm, 0.3 μm, 0.4 μm, 0.5 μm, 0.6 μm, 0.7 μm, 0.8 μm, 0.9 μm, 1 μm, 2 μm, 3 μm, 4 μm, 5 μm, 6 μm, 7 μm, 8 μm, 9 μm, 10 μm, 20 μm, 30 μm, 40 μm, 50 μm, 60 μm, 70 μm, 80 μm, 90 μm, 100 μm, 200 μm, 300 μm, 400 μm, 500 μm, or any value therebetween. In some embodiments, the displacement capacitance has an average height of at most about 500 μm, 400 μm, 300 μm, 200 μm, 100 μm, 90 μm, 80 μm, 70 μm, 60 μm, 50 μm, 40 μm, 30 μm, 20 μm, 10 μm, 9 μm, 8 μm, 7 μm, 6 μm, 5 μm, 4 μm, 3 μm, 2 μm, 1 μm, 0.9 μm, 0.8 μm, 0.7 μm, 0.6 μm, 0.5 μm, 0.4 μm, 0.3 μm, 0.2 μm, 0.1 μm, 0.09 μm, 0.08 μm, 0.07 μm, 0.06 μm, 0.05 μm, 0.04 μm, 0.03 μm, 0.02 μm, 0.01 μm, or any value therebetween.

[0107] The gap filling fluid can serve multiple purposes. First, in an electro-wetting device, the gap filling fluid can increase the electro-wetting force by replacing a low dielectric constant medium, such as air, with a higher dielectric constant liquid. The switch from a low dielectric constant medium to a higher dielectric constant medium increases the capacitance between the electrode and the manipulated fluid, thus increasing the charge on both the electrode and the manipulated fluid and increasing the applied force. Second, by replacing air, the gap filling fluid reduces thermal expansion and improves heat transfer between the substrate and the first surface, thereby enabling faster heating and cooling of the surface of the manipulated fluid and reducing expansion and contraction in the region under the film layer. Third, the gap filling fluid provides adhesive properties.

[0108] In some embodiments, the gap filling liquid is a gel, paste, grease, high viscosity oil, low viscosity oil, or a combination thereof. In some embodiments, the gap filling liquid is a silicone paste, lithium grease, silicone grease, thermal paste, dyed grease, or a combination thereof.

[0109] In some embodiments, the gap filling fluid is a capillary liquid, which is a liquid that can wet both the first surface and the substrate, generating a capillary pressure that reduces the distance between the substrate and the first surface. The reduced distance between the substrate and the first surface further increases the capillary pressure, thus further reducing the distance between the substrate and the first surface. This wetting behavior positions the first surface flat and uniform on the substrate and improves various characteristics of the device as described above. The capillary pressure is

[0110] [Number] can be defined as, where, as shown in FIGS. 6A and 6B, P0 is the atmospheric pressure, γ is the surface energy of the capillary liquid, θ is the contact angle of the capillary liquid with the substrate and the first surface, and d is the thickness of the capillary liquid at the edge of the liquid line. In practice, θ is close to zero, and the net pressure applied to the first surface is approximately

[0111] [Number] .

[0112] To provide good adhesion, the capillary liquid should have a contact angle of less than 90 degrees with both the substrate and the first surface.

[0113] In some embodiments, the capillary liquid has a contact angle of less than about 90 degrees with the substrate. In some embodiments, the capillary liquid has a contact angle with the substrate or the sealant layer of at least about 1 degree, 2 degrees, 3 degrees, 4 degrees, 5 degrees, 6 degrees, 7 degrees, 8 degrees, 9 degrees, 10 degrees, 20 degrees, 30 degrees, 40 degrees, 50 degrees, 60 degrees, 70 degrees, 80 degrees, 90 degrees, or any value therebetween. In some embodiments, the capillary liquid has a contact angle with the substrate of at most about 90 degrees, 80 degrees, 70 degrees, 60 degrees, 50 degrees, 40 degrees, 30 degrees, 20 degrees, 10 degrees, 9 degrees, 8 degrees, 7 degrees, 6 degrees, 5 degrees, 4 degrees, 3 degrees, 2 degrees, 1 degree, or any value therebetween.

[0114] In some embodiments, the capillary liquid has a contact angle with the first surface of less than about 90 degrees. In some embodiments, the capillary liquid has a contact angle with the first surface of at least about 1 degree, 2 degrees, 3 degrees, 4 degrees, 5 degrees, 6 degrees, 7 degrees, 8 degrees, 9 degrees, 10 degrees, 20 degrees, 30 degrees, 40 degrees, 50 degrees, 60 degrees, 70 degrees, 80 degrees, 90 degrees, or any value therebetween. In some embodiments, the capillary liquid has a contact angle with the first surface of at most about 90 degrees, 80 degrees, 70 degrees, 60 degrees, 50 degrees, 40 degrees, 30 degrees, 20 degrees, 10 degrees, 9 degrees, 8 degrees, 7 degrees, 6 degrees, 5 degrees, 4 degrees, 3 degrees, 2 degrees, 1 degree, or any value therebetween. In some embodiments, a secondary coating can be applied to the first surface to reduce the contact angle between the capillary fluid and the first surface.

[0115] In some embodiments, the capillary liquid is a hydrocarbon oil, a silicone oil, a fluorinated oil, a liquid acrylate, or a combination thereof. In some embodiments, the capillary liquid is a hydrocarbon oil selected from mineral oil, medium-chain alkanes, polyalphaolefins, and combinations thereof. In some embodiments, the capillary liquid is a silicone oil selected from methyl silicone oil, methylphenyl silicone oil, fluorosilicone oil, other silicone oils, or combinations thereof. In some embodiments, the capillary liquid is a fluorinated oil selected from perfluoropolyethers, fluoroacrylates, or combinations thereof.

[0116] In some embodiments, the gap filling liquid further comprises at least one additive. In some embodiments, the at least one additive is a rheology modifier, a filler, a solvent, a surfactant, a dye, or a combination thereof. In some embodiments, the additive enhances the performance of the gap filling liquid. Rheology modifiers, fillers, and solvents can help to adjust the viscosity of the liquid and can impart non-Newtonian flow characteristics to the liquid. Fillers can help to improve material properties such as thermal conductivity or dielectric constant. Dyes can be useful for bubble detection after application of the gap filling liquid.

[0117] In some embodiments, the substrate can be modified. In some embodiments, the substrate can be modified by applying a secondary coating to the substrate or by functionalizing the surface of the substrate. Either the secondary coating or the surface functionalization can be selected to improve the affinity of the substrate for the gap filling fluid.

[0118] In some embodiments, the modification can be selected to provide other properties such as durability, breakdown voltage, electrical resistivity, dielectric constant, environmental impact, elasticity, coefficient of thermal expansion, thermal conductivity, or combinations thereof.

[0119] In some embodiments, the substrate includes a secondary coating selected from parylene, other vapor deposition coatings, fluoropolymers, polyurethanes, acrylics, silicones, polyolefins, or combinations thereof. In some embodiments, the substrate includes a functionalized surface selected from silanes, other chemical vapor deposition precursors, other physical vapor deposition precursors, or combinations thereof.

[0120] In some embodiments, the first surface can be modified. In some embodiments, the first surface can be modified by applying a secondary coating to the film layer or by functionalizing the surface of the film layer. Either the secondary coating or the surface functionalization can be selected to improve the affinity of the first surface for the gap filling fluid.

[0121] In some embodiments, the gap filling fluid is either an insulating liquid or a conductive liquid.

[0122] In some embodiments, the device further includes a vacuum between the substrate and the first surface. In some embodiments, the vacuum can achieve the same properties as the gap filling fluid.

[0123] In some embodiments, the apparatus may further comprise a film frame configured to support the first surface. In some embodiments, the film frame is configured to maintain or generate tension in the film layer of the first surface. In some embodiments, the film frame is configured to generate a vacuum pressure between the substrate and the first surface.

[0124] In some embodiments, the film frame includes a fluid dispensing unit. In some embodiments, the frame is configured to dispense a liquid layer.

[0125] In some embodiments, the film frame is attached to the first surface around the first surface. In some embodiments, the first surface is attached to the film frame using an adhesive. In some embodiments, the adhesive is a wet adhesive or a dry adhesive. In some embodiments, the adhesive is a thermal adhesive. These adhesion strategies can be implemented selectively in the region of the film (e.g., along the periphery of the frame) or over the entire surface of the film.

[0126] In some embodiments, the first surface is about 0.0001 cm 2 ~ about 10000 cm 2 including a working area. The working area is the area of the first surface configured to contact the fluid being manipulated. In some embodiments, the first surface is at least about 0.0001 cm 2 0.0002 cm 2 0.0003 cm 2 0.0004 cm 2 0.0005 cm 2 0.0006 cm 2 0.0007 cm 2 0.0008 cm 2 0.0009 cm 2 0.001 cm 2 0.002 cm 2 0.003 cm 2 0.004 cm 2, 0.005 cm 2 , 0.006 cm 2 , 0.007 cm 2 , 0.008 cm 2 , 0.009 cm 2 , 0.01 cm 2 , 0.02 cm 2 , 0.03 cm 2 , 0.04 cm 2 , 0.05 cm 2 , 0.06 cm 2 , 0.07 cm 2 , 0.08 cm 2 , 0.09 cm 2 , 0.1 cm 2 , 0.2 cm 2 , 0.3 cm 2 , 0.4 cm 2 , 0.5 cm 2 , 0.6 cm 2 , 0.7 cm 2 , 0.8 cm 2 , 0.9 cm 2 , 1 cm 2 , 2 cm 2 , 3 cm 2 , 4 cm 2 , 5 cm 2 , 6 cm 2 , 7 cm 2 , 8 cm 2 , 9 cm 2 , 10 cm 2 , 20 cm 2 , 30 cm 2 , 40 cm 2 , 50 cm 2 , 60 cm 2 , 70 cm 2 , 80 cm 2 , 90 cm 2 , 100 cm 2 , 200 cm 2 , 300 cm 2 , 400 cm 2 , 500 cm 2 , 600 cm 2 , 700 cm 2 , 800 cm 2 , 900 cm 2 , 1000 cm 2 , 2000 cm 2 , 3000 cm 2, 4000 cm 2 , 5000 cm 2 , 6000 cm 2 , 7000 cm 2 , 8000 cm 2 , 9000 cm 2 , 10000 cm 2 , or includes a working area of any value therebetween. In some embodiments, the first surface is at most about 10000 cm 2 , 9000 cm 2 , 8000 cm 2 , 7000 cm 2 , 6000 cm 2 , 5000 cm 2 , 4000 cm 2 , 3000 cm 2 , 2000 cm 2 , 1000 cm 2 , 900 cm 2 , 800 cm 2 , 700 cm 2 , 600 cm 2 , 500 cm 2 , 400 cm 2 , 300 cm 2 , 200 cm 2 , 100 cm 2 , 90 cm 2 , 80 cm 2 , 70 cm 2 , 60 cm 2 , 50 cm 2 , 40 cm 2 , 30 cm 2 , 20 cm 2 , 10 cm 2 , 9 cm 2 , 8 cm 2 , 7 cm 2 , 6 cm 2 , 5 cm 2 , 4 cm 2 , 3 cm 2 , 2 cm 2 , 1 cm 2 , 0.9 cm 2 , 0.8 cm 2 , 0.7 cm 2 , 0.6 cm 2 , 0.5 cm 2 , 0.4 cm 2 , 0.3 cm2 , 0.2 cm 2 , 0.1 cm 2 , 0.09 cm 2 , 0.08 cm 2 , 0.07 cm 2 , 0.06 cm 2 , 0.05 cm 2 , 0.04 cm 2 , 0.03 cm 2 , 0.02 cm 2 , 0.01 cm 2 , 0.009 cm 2 , 0.008 cm 2 , 0.007 cm 2 , 0.006 cm 2 , 0.005 cm 2 , 0.004 cm 2 , 0.003 cm 2 , 0.002 cm 2 , 0.001 cm 2 , 0.0009 cm 2 , 0.0008 cm 2 , 0.0007 cm 2 , 0.0006 cm 2 , 0.0005 cm 2 , 0.0004 cm 2 , 0.0003 cm 2 , 0.0002 cm 2 , 0.0001 cm 2 , or includes a working area of any value between them.

[0127] In some embodiments, the apparatus described herein can be used to manipulate fluids. In some embodiments, the manipulated fluid includes inorganic ions, organic ions, proteins, DNA, RNA, surfactants, oil droplets, magnetic beads, nanoparticles, microparticles, polymers, organic compounds, hormones, or combinations thereof. In some embodiments, the manipulated fluid includes water, ethanol, isopropanol, methanol, acetone, formaldehyde, methyl ethyl ketone, acetamide, ethylene glycol, propylene glycol, dimethyl sulfoxide, dimethylformamide, acetic acid, glycerol, or combinations thereof.

[0128] Method of applying a surface coating In another aspect, the present disclosure provides a method of coating a surface for fluid operation. In some embodiments, the method includes applying a film layer to the surface and applying a liquid layer to the film layer.

[0129] In some embodiments, the surface coating can be applied by at least one of spin coating, spray coating, dip coating, needle dispensing, vapor deposition, or combinations thereof. In some embodiments, applying the film layer includes stretching and bonding the thin film to the surface. The thin film can be stretched to eliminate wrinkles and ensure further smoothness. The thin film can be held on the electrode array by heat or thermal bonding, by applying a vacuum, by electrostatic forces, or by mechanical means.

[0130] In some embodiments, the surface coating is formed by spray-coating a film layer onto the surface. The film layer can be cured. Then, a lubricating layer is sprayed or dispensed onto the film layer.

[0131] In some embodiments, the surface coating is formed by attaching a film layer to a film frame. Then, the film frame is attached to the surface. Then, a lubricating layer is sprayed or dispensed onto the film layer.

[0132] In some embodiments, the film layer is formed by flowing a material across the surface, such as through an inner channel formed by a tube. The lubricating layer can be applied to the film layer by flowing a liquid over the film layer.

[0133] In some embodiments, the thickness of the film layer is from about 0.1 μm to about 1000 μm. In some embodiments, the film layer has a thickness of at least about 0.1 μm, 0.2 μm, 0.3 μm, 0.4 μm, 0.5 μm, 0.6 μm, 0.7 μm, 0.8 μm, 0.9 μm, 1 μm, 2 μm, 3 μm, 4 μm, 5 μm, 6 μm, 7 μm, 8 μm, 9 μm, 10 μm, 20 μm, 30 μm, 40 μm, 50 μm, 60 μm, 70 μm, 80 μm, 90 μm, 100 μm, 200 μm, 300 μm, 400 μm, 500 μm, 600 μm, 700 μm, 800 μm, 900 μm, 1000 μm, or any value therebetween. In some embodiments, the film layer is at most about 1000 μm, 900 μm, 800 μm, 700 μm, 600 μm, 500 μm, 400 μm, 300 μm, 200 μm, 100 μm, 90 μm, 80 μm, 70 μm, 60 μm, 50 μm, 40 μm, 30 μm, 20 μm, 10 μm, 9 μm, 8 μm, 7 μm, 6 μm, 5 μm, 4 μm, 3 μm, 2 μm, 1 μm, 0.9 μm, 0.8 μm, 0.7 μm, 0.6 μm, 0.5 μm, 0.4 μm, 0.3 μm, 0.2 μm, 0.1 μm or any value therebetween.

[0134] In some embodiments, the film layer is a smooth surface. At least one 10000 μm of the surface intended to contact the fluid being manipulated 2 portion exists, any 2000 μm of which 2When the part has an Ra of less than 10 μm and a Wenzel roughness coefficient of less than 2, the fluid operating surface is smooth. In some embodiments, the film layer has an Ra of from about 100 μm to about 0 μm. In some embodiments, the film layer has an Ra of from about 100 nanometers (nm) to about 0 nm. In some embodiments, the film layer has an Ra of at least about 0 μm, 0.01 μm, 0.02 μm, 0.03 μm, 0.04 μm, 0.05 μm, 0.06 μm, 0.07 μm, 0.08 μm, 0.09 μm, 0.1 μm, 0.2 μm, 0.3 μm, 0.4 μm, 0.5 μm, 0.6 μm, 0.7 μm, 0.8 μm, 0.9 μm, 1 μm, 2 μm, 3 μm, 4 μm, 5 μm, 6 μm, 7 μm, 8 μm, 9 μm, 10 μm, 20 μm, 30 μm, 40 μm, 50 μm, 60 μm, 70 μm, 80 μm, 90 μm, 100 μm, or any value therebetween. In some embodiments, the film layer has an Ra of up to about μm, 90 μm, 80 μm, 70 μm, 60 μm, 50 μm, 40 μm, 30 μm, 20 μm, 10 μm, 9 μm, 8 μm, 7 μm, 6 μm, 5 μm, 4 μm, 3 μm, 2 μm, 1 μm, 0.9 μm, 0.8 μm, 0.7 μm, 0.6 μm, 0.5 μm, 0.4 μm, 0.3 μm, 0.2 μm, 0.1 μm, 0.09 μm, 0.08 μm, 0.07 μm, 0.06 μm, 0.05 μm, 0.04 μm, 0.03 μm, 0.02 μm, 0.01 μm, 0 μm, or any value therebetween.

[0135] In some embodiments, the film layer comprises one or more polymer films, inorganic films, composite films, or combinations thereof. In some embodiments, the film layer is a composite film layer in which two or more films are laminated. In some embodiments, the film layer is a composite film layer in which three or more films are laminated. In some embodiments, the film layer is a composite film layer in which four or more films are laminated. In some embodiments, the film layer is a composite film layer in which five or more films are laminated. These composite films utilize the various properties of each material used.

[0136] In some embodiments, the film layer may comprise an insulating dielectric material. In some embodiments, the film layer comprises polyethylene, polypropylene, polystyrene, polyether ether ketone (PEEK), polyimide, polyacetal, polysulfone, polyphenylene ether, polyphenylene sulfide (PPS), polyvinyl chloride, synthetic rubber, natural rubber, neoprene, nylon, polyacrylonitrile, polyvinyl butyral, silicone, parafilm, polyethylene terephthalate, polybutylene terephthalate, polyamide, polyoxymethylene, polycarbonate, polymethylpentene, polyphenylene oxide (polyphenylene ether), polyphthalamide (PPA), polylactic acid, synthetic cellulose ether (e.g., methyl cellulose, ethyl cellulose, propyl cellulose, hydroxyethyl cellulose, hydroxyethyl cellulose, hydroxypropyl cellulose (HPC), hydroxyethylmethyl cellulose, hydroxypropylmethyl cellulose (HPMC), ethylhydroxyethyl cellulose), paraffin, microcrystalline wax, epoxy, polytetrafluoroethylene (PTFE), tetrafluoroethylene (TFE), fluorinated ethylene propylene copolymer (FEP), polyvinylidene fluoride (PVDF), perfluoroalkoxy tetrafluoroethylene copolymer (PFA), perfluoromethyl vinyl ether copolymer (MFA), ethylene chlorotrifluoroethylene copolymer (ECTFE), ethylene-tetrafluoroethylene copolymer (ETFE), perfluoropolyether (PFPE), polychlorotetrafluoroethylene (PCTFE), ceramic, borosilicate glass, quartz, alumina, silica, clay mineral, bentonite, kaolinite, vermiculite, graphite, molybdenum disulfide, mica, boron nitride, sodium formate, sodium oleate, sodium palmitate, sodium sulfate, sodium alginate, other polymer materials, other ceramic materials, or combinations thereof.

[0137] In some embodiments, the film layer can be modified. In some embodiments, the film layer can be modified by applying a secondary coating to the film layer or by functionalizing the surface of the film layer. Either the secondary coating or the surface functionalization can be selected to improve the affinity of the film layer for the liquid layer. The modification of the film layer can be achieved in either the liquid phase or the gas phase. The film layer can be modified on either side, and both sides of the film layer can include the same or different modifications. The film layer can be modified to improve hydrophobicity and fluid handling.

[0138] In some embodiments, the modification can be selected to provide other properties such as durability, dielectric breakdown, electrical resistivity, permittivity, environmental impact, elasticity, coefficient of thermal expansion, thermal conductivity, or combinations thereof.

[0139] In some embodiments, the liquid layer can diffuse into the film layer and swell the film layer.

[0140] In some embodiments, the liquid layer is non-uniform. In some embodiments, the liquid layer has an average initial thickness of from about 0.1 μm to about 500 μm. In some embodiments, the liquid layer has a thickness of at least about 0.1 μm, 0.2 μm, 0.3 μm, 0.4 μm, 0.5 μm, 0.6 μm, 0.7 μm, 0.8 μm, 0.9 μm, 1 μm, 2 μm, 3 μm, 4 μm, 5 μm, 6 μm, 7 μm, 8 μm, 9 μm, 10 μm, 20 μm, 30 μm, 40 μm, 50 μm, 60 μm, 70 μm, 80 μm, 90 μm, 100 μm, 200 μm, 300 μm, 400 μm, 500 μm, or any value therebetween. In some embodiments, the liquid layer has a thickness of up to about 500 μm, 400 μm, 300 μm, 200 μm, 100 μm, 90 μm, 80 μm, 70 μm, 60 μm, 50 μm, 40 μm, 30 μm, 20 μm, 10 μm, 9 μm, 8 μm, 7 μm, 6 μm, 5 μm, 4 μm, 3 μm, 2 μm, 1 μm, 0.9 μm, 0.8 μm, 0.7 μm, 0.6 μm, 0.5 μm, 0.4 μm, 0.3 μm, 0.2 μm, 0.1 μm, or any value therebetween.

[0141] The viscosity of the liquid layer can be selected to optimize the fluidity of the liquid layer, reduce drag, and enhance durability. In some embodiments, the liquid layer has a viscosity of from about 0.5 cSt to about 100 cSt. In some embodiments, the liquid layer has a viscosity of from about 0 cSt to about 20 cSt. In some embodiments, the liquid layer has a viscosity of from about 5 cSt to about 20 cSt. In some embodiments, the liquid layer has a viscosity of at least about 0 cSt, 0.1 cSt, 0.2 cSt, 0.3 cSt, 0.4 cSt, 0.5 cSt, 0.6 cSt, 0.7 cSt, 0.8 cSt, 0.9 cSt, 1 cSt, 2 cSt, 3 cSt, 4 cSt, 5 cSt, 6 cSt, 7 cSt, 8 cSt, 9 cSt, 10 cSt, 20 cSt, 30 cSt, 40 cSt, 50 cSt, 60 cSt, 70 cSt, 80 cSt, 90 cSt, 100 cSt, or any value therebetween. In some embodiments, the liquid layer has a viscosity of at most about 100 cSt, 90 cSt, 80 cSt, 70 cSt, 60 cSt, 50 cSt, 40 cSt, 30 cSt, 20 cSt, 10 cSt, 9 cSt, 8 cSt, 7 cSt, 6 cSt, 5 cSt, 4 cSt, 3 cSt, 2 cSt, 1 cSt, 0.9 cSt, 0.8 cSt, 0.7 cSt, 0.6 cSt, 0.5 cSt, or any value therebetween. The values provided herein for the viscosity of the liquid layer can be measured when the liquid layer is at room temperature.

[0142] In some embodiments, the liquid layer has a static contact angle with the film layer of about 10 degrees or less. The small static contact angle helps to improve lubricity and reduce fouling and pinning during fluid operation. In some embodiments, the liquid layer has a static contact angle with the film layer of at least about 0.1 degrees, 0.2 degrees, 0.3 degrees, 0.4 degrees, 0.5 degrees, 0.6 degrees, 0.7 degrees, 0.8 degrees, 0.9 degrees, 1 degree, 2 degrees, 3 degrees, 4 degrees, 5 degrees, 6 degrees, 7 degrees, 8 degrees, 9 degrees, 10 degrees, or any value in between. In some embodiments, the liquid layer has a static contact angle with the film layer of at most about 10 degrees, 9 degrees, 8 degrees, 7 degrees, 6 degrees, 5 degrees, 4 degrees, 3 degrees, 2 degrees, 1 degree, 0.9 degrees, 0.8 degrees, 0.7 degrees, 0.6 degrees, 0.5 degrees, 0.4 degrees, 0.3 degrees, 0.2 degrees, 0.1 degrees, or any value in between.

[0143] In some embodiments, the liquid layer is a lubricating layer. The lubricating layer improves the overall fluid mobility by reducing the friction between the film layer and the droplets, preventing droplet pinning, reducing fouling, and reducing contact angle hysteresis. Good fluid mobility is defined by the ability to move a fluid accurately, reliably, at high speed, and over a long period of time without pinning and fouling on the surface.

[0144] In some embodiments, the lubricating layer is selected for its affinity to the film layer and immiscibility with the fluid being operated. In some embodiments, the lubricating layer is a hydrocarbon layer, a silicone layer, a fluorinated layer, or a combination thereof.

[0145] In some embodiments, the lubricating layer includes polydimethylsiloxane, polymethylhydrogen siloxane / hydrogen silicone oil, aminosilicone oil, phenylmethyl silicone oil, diphenyl silicone oil, vinyl silicone oil, hydroxysilicone oil, cyclopolysiloxane, polyalkylene oxide silicone, silicone resin, perfluoropolyether (PFPE), perfluoroalkane, fluorinated ionic fluid, fluorinated silicone oil, perfluoroalkyl ether, perfluorotri-n-butylamine (FC-40), hydrofluoroether (HFE) liquid, ionic liquid, mineral oil, ferromagnetic fluid, polyphenyl ether, vegetable oil, esters of saturated fatty acids and dibasic acids, grease, fatty acid, triglyceride, polyalphaolefin, polyglycol hydrocarbon, other alkanes, other non-hydrocarbon synthetic oils, or combinations thereof.

[0146] In some embodiments, the lubricating layer may include additives. In some embodiments, the additives are rheology modifiers, fillers, solvents, surfactants, dyes, or combinations thereof. Rheology modifiers, fillers, and solvents may help to adjust the viscosity of the liquid and may impart non-Newtonian flow characteristics to the liquid. Fillers may help to improve material properties such as thermal conductivity and dielectric constant and may also change rheological properties. Surfactants and solvents may help to adjust the surface energy of the lubricating layer with respect to air and the fluid being manipulated.

[0147] In some embodiments, some or all of the surface coating may be removed and replaced. In some embodiments, the surface coating may be used once. In some embodiments, the surface coating may be used multiple times. In some embodiments, the coating may be permanent.

[0148] In some embodiments, the surface coatings described herein can be applied to surfaces intended to contact a fluid. In some embodiments, non-limiting examples of surfaces intended to contact a fluid include cannulas, connectors, catheters (e.g., central line, peripherally inserted central catheter (PICC) line, urinary, vascular, peritoneal dialysis, and central venous catheters), catheter connectors (e.g., Leur-Lok and needleless connectors), clamps, skin hooks, cuffs, retractors, shunts, needles, capillaries, endotracheal tubes, ventilators, associated ventilator tubes, drug delivery media, syringes, microscope slides, plates, films, laboratory work surfaces, wells, well plates, Petri dishes, tiles, jars, flasks, beakers, vials, test tubes, tube connectors, columns, containers, cuvettes, bottles, drums, baths, tanks, organs, organ implants, or organ components (e.g., intrauterine devices, defibrillators, corneas, breasts, knee replacements, and hip replacement implants), artificial organs or their components (e.g., heart valves, ventricular assist devices, total artificial hearts, cochlear implants, visual prosthetics, and their components), dental tools, dental implants (e.g., root form, plate form, and subperiosteal implants), biosensors (e.g., glucose and insulin monitors, blood oxygen sensors, hemoglobin sensors, bioelectromechanical devices (bioMEM), sepsis diagnostic sensors, and other protein and enzyme sensors), bioelectrodes, endoscopes (hysteroscopes, cystoscopes, amnioscopes, laparoscopes, gastroscopes, enteroscopes, bronchoscopes, esophagoscopes, rhinoscopes, arthroscopes, proctoscopes, colonoscopes, nephroscopes, angioscopes, thoracoscopes, esophagoscopes, laryngoscopes, and brain scopes), wound dressings (e.g., bandages, sutures, staples), and combinations thereof.Cannulas, connectors, catheters (e.g., central lines, peripherally inserted central catheters (PICC) lines, urinary, vascular, peritoneal dialysis, and central venous catheters), catheter connectors (e.g., Leur-Lok and needleless connectors), clamps, skin hooks, cuffs, retractors, shunts, needles, capillaries, endotracheal tubes, ventilators, related ventilator tubes, drug delivery media, syringes, microscope slides, plates, films, laboratory work surfaces, wells, well plates, Petri dishes, tiles, jars, flasks, beakers, vials, test tubes, tube connectors, columns, containers, cuvettes, bottles, drums, baths, tanks, organs, organ implants, or organ components (e.g., intrauterine contraceptive devices, defibrillators, corneas, breasts, artificial knee joints, and artificial hip implants), artificial organs or their components (e.g., heart valves, ventricular assist devices, total artificial hearts, cochlear implants, visual prostheses, and their components), dental tools, dental implants (e.g., root form, plate form, and subperiosteal implants). Biosensors (e.g., glucose and insulin monitors, blood oxygen sensors, hemoglobin sensors, biomicroelectromechanical devices (bioMEM), sepsis diagnostic sensors, and other protein and enzyme sensors), Bioelectrodes, endoscopes (hysteroscopes, cystoscopes, amnioscopes, laparoscopes, gastroscopes, enteroscopes, bronchoscopes, esophagoscopes, nasal scopes, arthroscopes, proctoscopes, colonoscopes, nephroscopes, angioscopes, thoracoscopes, esophagoscopes, laryngoscopes, and cranioscopes), wound dressings (e.g., bandages, sutures, staples), and combinations thereof are coated on the surfaces.

[0149] In some embodiments, the coatings described herein can be applied to devices such as research arrays and diagnostic arrays. Examples of research and diagnostic arrays can include sample preparation, amplification, rolling circle amplification, bridge amplification, sequencing, circular consensus sequencing, next generation sequencing, polymerase chain reaction, enzymatic polymer synthesis, and sample detection arrays.

Examples

[0150] The following examples are for illustrative purposes only and do not limit the scope of the present invention.

[0151] Example 1: Preparation of an Exchangeable Surface Coating for Electro-Wetting An exchangeable surface coating was prepared for electro-wetting. A substrate having an array of electrodes was coated with a parylene sealant layer. The thickness of the parylene sealant layer was from 0.1 μm to 50 μm, such as 2 μm, for example. Next, a silicone oil gap filling liquid was applied to the substrate coated with parylene. The silicone oil gap filling liquid had a viscosity of from 0.65 cSt to 1,000 cSt, such as 5 cSt, for example. Next, a PET thin film coated with silicone was applied onto the gap filling liquid. Alternatively, the PET thin film may be applied before applying the silicone gap filling liquid. The thickness of the PET thin film was from 0.5 μm to 1,000 μm, such as 13 μm, for example. Next, a silicone oil liquid layer with a thickness of 50 nm to 500 μm was applied onto the PET thin film. The silicone oil liquid layer had a viscosity of from 0.65 cSt to 1,000 cSt, such as 5 cSt, for example. The coating can be removed leaving a part of the substrate, the electrodes, and the sealant layer.

[0152] Figure 7 is a diagram showing the structure of an exchangeable surface coating for electro-wetting.

[0153] Example 2: Preparation of a Permanent Surface Coating for Electro-Wetting A permanent surface coating was prepared for electro-wetting. A substrate having an array of electrodes was coated with a thin parylene sealant layer. The thickness of the parylene sealant layer was from 0.1 μm to 50 μm, such as 2 μm, for example. A silicone coating was applied onto the parylene sealant layer. The thickness of the silicone coating was from 50 nm to 25 μm, such as 1 μm, for example. Next, a silicone oil liquid layer was applied onto the silicone coating. The silicone oil liquid layer had a viscosity of from 0.65 cSt to 1,000 cSt, such as 5 cSt, for example.

[0154] Figure 8 is a diagram showing the structure of a permanent surface coating for electro-wetting.

[0155] Example 3: Preparation of an Exchangeable Surface Coating for Gravitational Fluid Manipulation An exchangeable surface coating was prepared for gravitational fluid manipulation. The substrate was coated with a silicone oil gap filling liquid. The silicone oil gap filling liquid had a viscosity of 0.65 cSt to 1,000 cSt, for example 5 cSt. Next, a silicone-coated PET thin film layer was applied onto the gap filling liquid. The thickness of the PET thin film layer was 0.5 μm to 1,000 μm, for example 13 μm. Then, a silicone oil liquid layer having a thickness of 50 nm to 25 μm, for example 1 μm, was applied onto the PET thin film. The coating can be removed leaving a part of the substrate and the gap filling liquid.

[0156] Figure 9 is a diagram showing the structure of an exchangeable surface coating for gravitational fluid manipulation.

[0157] Example 4: Coating of a Surface for Contact with a Fluid A thin film layer was applied to the surface. The thin film layer was not textured (e.g., completely smooth, substantially smooth, smooth within an acceptable threshold or within a predetermined threshold, etc.). A liquid layer was applied to the film layer. The liquid layer was an oil layer. Figure 10A provides exemplary data showing the maximum droplet velocity as a function of the true viscosity of the liquid layer. Generally, as the true viscosity of the liquid layer increased, the maximum droplet velocity decreased. Note that 1 mPa*s = 1 cSt. The liquid layer had a static contact angle with the thin film layer of less than 10 degrees. Figure 10B provides exemplary data showing the electrowetting on dielectric (EWOD) force on a dielectric measured at various electrowetting voltages. The EWOD force was measured by sliding angle measurement for two different thin film layers (one 0.012 mm thick and the other 0.019 mm thick) at various electrowetting voltages between 250 volts and 290 volts. The thicker thin film layer consistently measured a lower electrowetting force than the thinner thin film layer. Figure 10C provides exemplary data showing thickness data for various film regions of the thin film layer. As shown, the thickness varies between approximately 11.5 μm and approximately 12.0 μm. Figure 10D 2 , 5 μm 2 , and 1 μm 2 provides exemplary data showing the roughness values of three different thin film layers having different sample area sizes. As shown, the Ra roughness of Sample 1 was approximately 10.73 nm for an average RMS20 (corresponding to a sample area of 20 μm 2 ), approximately 3.54 nm for an average RMS5 (corresponding to a sample area of 5 μm 2 ), and approximately 2.54 nm for an average RMS1 (1 μm 2(corresponding to the sample area) was about 1.31 nm. As shown, the Ra roughness of sample 2 was such that the average RMS20g was about 29.26 nm, the average RMS5 was about 20.39 nm, and the average RMS1 was about 4.02 nm. As shown, the Ra roughness of sample 3 was such that the average RMS20 was about 12.13 nm, the average RMS5 was about 4.71 nm, and the average RMS1 was about 2.52 nm.

[0158] Preferred embodiments of the present invention have been shown and described herein, but it will be apparent to those skilled in the art that such embodiments are provided by way of example only. The present invention is not intended to be limited by the specific examples provided herein. Although described with reference to the foregoing specification, the description and illustration of the embodiments herein are not intended to be construed in a limiting sense. Numerous variations, modifications, and substitutions will occur to those skilled in the art without departing from the present invention. Further, it should be understood that all aspects of the present invention are not limited to the specific depictions, configurations, or relative ratios described herein, which may vary depending on various conditions and variables. It should be understood that various alternative forms of the embodiments of the present invention described herein may be employed in practicing the present invention. Accordingly, it is intended that the present invention will further encompass any such alternatives, modifications, variations, or equivalents thereof. The following claims define the scope of the present invention, and it is intended that methods and structures within the scope of these claims and their equivalents be covered thereby.

Claims

1. A method for coating a surface for contact with a fluid, A step of applying a film layer to the surface, wherein the film layer is not textured. A step of applying a liquid layer to a film layer, wherein the liquid layer has a viscosity of about 0.5 centistokes (cSt) to about 100 cSt and an average initial thickness in the range of about 0.01 micrometers to about 500 micrometers. Methods that include...

2. The method according to claim 1, wherein the film layer has an average roughness (Ra) of about 100 μm to about 0 μm.

3. The method according to claim 1 or 2, wherein the surface contains a silicone gap-filling liquid.

4. The liquid layer is a lubricating layer, The method according to claim 1, wherein the lubricating layer is a hydrocarbon layer, a silicone layer, a fluorinated layer, or a combination thereof.

5. The liquid layer is a lubricating layer, The method according to claim 1, wherein the lubricating layer comprises polydimethylsiloxane, polymethylhydrogensiloxane / hydrogen silicone oil, aminosilicone oil, phenylmethylsilicone oil, diphenylsilicone oil, vinylsilicone oil, hydroxysilicone oil, cyclosiloxane, polyalkylene oxide silicone, silicone resin, perfluoropolyether (PFPE), perfluoroalkane, fluorinated ionic fluid, fluorinated silicone oil, perfluoroalkyl ether, perfluorotri-n-butylamine (FC-40), hydrofluoroether (HFE) liquid, ionic liquid, mineral oil, ferromagnetic fluid, polyphenyl ether, vegetable oil, esters of saturated fatty acids and dibasic acids, grease, fatty acids, triglycerides, polyalphaolefin, polyglycol hydrocarbons, other alkanes, or other non-hydrocarbon synthetic oils.

6. The method according to claim 1, wherein the liquid layer further comprises at least one additive.

7. The method according to claim 6, wherein the at least one additive is a rheological modifier, a filler, a solvent, a surfactant, a dye, or a combination thereof.

8. The method according to claim 1, wherein the liquid layer can diffuse into the film layer and cause the film layer to swell.

9. The method according to claim 1, wherein the liquid layer has a static contact angle with the film layer of about 10 degrees to about 0 degrees.

10. The method according to claim 1, wherein the film layer comprises one or more polymer films, inorganic films, composite films, or combinations thereof.

11. A surface coating for contact with a fluid, A non-textured film layer, A liquid layer having a viscosity of approximately 0.5 cSt to approximately 100 cSt and an average initial thickness in the range of approximately 0.01 μm to approximately 500 μm. A surface coating, including

12. The surface coating according to claim 11, wherein the film layer has an average roughness (Ra) of about 100 μm to about 0 μm.

13. The surface coating according to claim 11 or 12, wherein the liquid layer is a lubricating layer.

14. The surface coating according to claim 13, wherein the lubricating layer is a hydrocarbon layer, a silicone layer, a fluorinated layer, or a combination thereof.

15. The surface coating according to claim 13, wherein the lubricating layer comprises polydimethylsiloxane, polymethylhydrogensiloxane / hydrogen silicone oil, aminosilicone oil, phenylmethylsilicone oil, diphenylsilicone oil, vinylsilicone oil, hydroxysilicone oil, cyclosiloxane, polyalkylene oxide silicone, silicone resin, perfluoropolyether (PFPE), perfluoroalkane, fluorinated ionic fluid, fluorinated silicone oil, perfluoroalkyl ether, perfluorotri-n-butylamine (FC-40), hydrofluoroether (HFE) liquid, ionic liquid, mineral oil, ferromagnetic fluid, polyphenyl ether, vegetable oil, esters of saturated fatty acids and dibasic acids, grease, fatty acids, triglycerides, polyalphaolefin, polyglycol hydrocarbons, other alkanes, or other non-hydrocarbon synthetic oils.

16. The surface coating according to claim 13, wherein the lubricating layer further comprises at least one additive.

17. The surface coating according to claim 16, wherein the at least one additive is a rheological modifier, a filler, a solvent, a surfactant, a dye, or a combination thereof.

18. The surface coating according to claim 11, wherein the liquid layer can diffuse into the film layer and cause the film layer to swell.

19. The surface coating according to claim 11, wherein the liquid layer has a static contact angle with the film layer of about 10 degrees or less.

20. The surface coating according to claim 11, wherein the film layer comprises one or more polymer films, inorganic films, composite films, or combinations thereof.

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