Oil Repellency Research Articles

Judicious Design and Rapid Manufacturing of a Flexible, Mechanically Resistant Liquid-Like Coating with Strong Bonding and Antifouling Abilities.

Fluorine-free liquid-repellent coatings have been highly demanded for a variety of applications. However, rapid formation of coatings possessing outstanding oil repellency and strong bonding ability as well as good mechanical strength (e.g., bendability, impact resistance, and scratch resistance) remains a grand challenge. Herein, a robust strategy to rapidly create fluorine-free oil-repellent coatings in only 30 s via rational design of a semi-interpenetrating polymer network structure is reported. The resulting coating manifests strong bonding capability both in air and underwater. More importantly, it not only provides unprecedented oil repellency, even to high-viscosity crude oil, but also achieves both excellent bendability and hardness. This simple yet effective design strategy opens up a new avenue to manufacture multifunctional materials and devices with desirable features and structural complexities for applications in sustainable antifouling, drag reduction, nondestructive transportation, liquid collection, and biomedicine, among other areas.

Synthesis of Bio-Based Non-Fluorinated Oil and Water Repellent Finishes for Cotton Fabric by Using Palmitic Acid, Succinic Acid, and Maleic Acid

ABSTRACT Oil and water repellency is very important for certain textile end products. Traditional durable oil and water repellents contain fluorine or formaldehyde-based substances. These substances have a long-term negative impact on the human health and natural environmental, and therefore, they are being banned. To address this problem, scientists are continuously working on the development of new sustainable alternatives. In this regard, present paper reports the results of the successful development, optimization, and application of two ecofriendly oil and water repellents for cotton fabrics. In case of the first oil and water repellent development, present research polymerizes the bio-based palmitic acid with formaldehyde-free bio-succinic acid. While in the second oil and water repellent, this research polymerizes the bio-based palmitic acid with formaldehyde-free maleic acid. The developed polymers provided comparable or better performance properties with reference to the C6-based commercial fluorocarbon. In addition, the proposed polymers were successfully characterized using X-ray diffraction (XRD) analysis, FTIR analysis, H-NMR spectroscopy, energy dispersive X-Ray (EDX) analysis, and SEM analysis).

Water and oil repellent coating on fabric using hollow cathode PECVD

Thin film deposition is a suitable process for textile finishing at a time when environmental protection is a global concern. Thin film technology for textile treatments does not only avoid the harmful chemistry and resulting hazardous waste of the wet chemistry, but limits the use of chemicals, water, etc., and do not require a drying system, resulting in a much lower energy consumption. The hollow cathode plasma enhanced chemical vapor deposition is one of the alternatives developed to overcome the wet processings disadvantages. Water and oil repellent finishes are applied through plasma polymerization of short chain perfluoroalkyls precursors. The key advantages of this technology are a high deposition rate and a good uniformity over large areas. However, hollow cathode is a high-density plasma source, appropriate for the deposition of inorganic layers, typically SiO2, but challenging for the deposition on fabrics without modifying their bulk properties or damaging their surface.In this work, we demonstrate the successful use of the hollow cathode technology to impart water and oil repellent properties on polyolefin textiles with fluorinated and silicone precursors. The effect of parameters such as power, pressure, gas composition and flow on water and oil repellency have been evaluated according to international standards, water contact angle and the film composition analysed through FTIR measurements. Water contact angles greater than 150°, i.e. superhydrophobic surface, and oil repellency grade of 4 have been obtained.

Laser-Induced Slippery Liquid-Infused Surfaces with Anticorrosion and Wear Resistance Properties on Aluminum Alloy Substrates.

Slippery liquid-infused surfaces (SLISs) are developed as a potential alternative to superhydrophobic surfaces (SHSs) to resolve the issues of poor durability in corrosion protection and wear resistance. In this work, we used a simple laser processing technology to prepare a SLIS on the aluminum alloy (7075) surface. The superhydrophobicities of the modified surface and the oil film formed by liquid injection make the corrosive medium difficult to directly contact the surface and thus have a significant effect on corrosion resistance. The water and oil repellent SLIS exhibits durable corrosion resistance and excellent tribological properties compared with the SHS. The anticorrosion and wear resistance performances provided by the composite film have been assessed by multiple methods including the electrochemical test, immersion test, and friction wear test. The results indicate that compared to the bare surface, laser-ablated surface (LAS), and fluoroalkyl silane-modified SHS, the SLIS composite coating has better corrosion resistance and wear resistance, which is of great significance to expand the potential applications of 7075 aluminum alloys. The work provides a research basis for expanding the practical application of SLISs in complex environments.

Selective Fabrication of Robust and Multifunctional Super Nonwetting Surfaces by Diverse Modifications of Zirconia-Ceria Nanocomposites.

The creation of surfaces with various super nonwetting properties is an ongoing challenge. We report diverse modifications of novel synthesized zirconia-ceria nanocomposites by different low surface energy agents to fabricate nanofluids capable of regulating surface wettability of mineral substrates to achieve selective superhydrophobic, superoleophobic-superhydrophilic, and superamphiphobic conditions. Surfaces treated with these nanofluids offer self-cleaning properties and effortless rolling-off behavior with sliding angles ≤7° for several liquids with surface tensions between 26 and 72.1 mN/m. The superamphiphobic nanofluid coating imparts nonstick properties to a solid surface whereby liquid drops can be effortlessly displaced on the coating with a near-zero tilt and conveniently lifted off using a needle tip, leaving no trace. Further, the superamphiphobic surface demonstrates good oil repellency toward ultralow surface tension liquids such as n-hexane and n-heptane. The superoleophobic-superhydrophilic surface repels oil droplets well regardless of whether it is in the air or underwater conditions. In addition, reaping the benefits of the ZrO2-CeO2 nanocomposites' photocatalysis feature, the superoleophobic-superhydrophilic coating exhibits self-cleaning ability by the degradation of color dyes. Modification of the wettability of substrates is carried out by a cost-effective and facile solution-immersion approach, which creates surfaces with hierarchical nano-submicron-scaled structures. The multipurpose coated surfaces have outstanding durability and mechanical stability. They also resist well high-temperature-high-pressure conditions, which will provide various practical applications in different fields, including the condensate banking removal in gas reservoirs or the separation of oil/water mixtures.

Bio-inspired PDA@WS2 polyacrylonitrile ultrafiltration membrane for the effective separation of saline oily wastewater and the removal of soluble dye

The use of membrane filtration for saline oily wastewater separation remains challenging for industry application despite the progress in membrane technology. The use of two-dimensional (2D) nanoparticles is well known for improving membrane properties, yet they are still vulnerable to fouling and operational inconsistencies. In providing solutions, bio-inspired PDA@WS2 PAN UF membrane was fabricated with tailored molecular weight cutoff (MWCO) and excellent selectivity for effective removal of oil and dye in a saline environment. At high salinity, the modified membrane with the lowest MWCO of 5308.53 Da and Stokes diameter of 2.17 nm showed sufficient separation of oil and dye of about 99.53% and 98.23% respectively. Concurrently sustaining high water permeability of 58.57 L m−2h−1 with free transport of monovalent and divalent salts. Moreover, due to the synergistic effect of the adhesive PDA with WS2 nanosheet and PAN, the modified membrane displayed outstanding oil repellency and antifouling properties of about 98.6%. Furthermore, excellent thermal stability between the temperature of 100–900 °C, and pressure stability ranging from 1 bar to 6 bar of the modified membranes was reported. Overall, the operational stability of the modified membrane was sustained with high removal of oil and dye, and permeation of salt over a 90 h long-term operation. Consequently, this study demonstrates the potential application of bio-inspired PDA@WS2 PAN membrane for the treatment of saline oily wastewater.

Tolerant chitosan/carboxymethyl cellulose@calcium composite films on nylon fabric for high-flux water/oil separation

Nacre as a natural organic–inorganic composite has outstanding mechanical toughness and oil repellency. Enlightened by nacre, we present here a novel strategy to fabricate superhydrophilic/underwater superoleophobic hybrid films on nylon fabric (NF). The hybrid films were constructed via facile and green layer-by-layer (LbL) assembly of calcium ion (Ca2+), chitosan (CS), and carboxymethyl cellulose (CMC) combined with biomimetic mineralization in CO2 atmosphere. The resulting NF exhibits excellent superoleophobicity underwater, anti-oil-fouling ability, and stability. Under the drive of gravity, the deposited fabric can selectively remove pure and corrosive water from various oil-containing water with preferable separation efficiencies, great water flux (>6903 L·m−2·h−1), favorable oil penetration pressure (1.47 kPa), and outstanding recyclability. Especially, the NF can still sustain high underwater oleophobicity after repeatedly separating oil/corrosive water for 80 times. The green preparation process, eco-friendly and durable coating, and good separation performance allow the as-fabricated NF to be applied in oily wastewater treatment.

Smart multi-responsive aramid aerogel fiber enabled self-powered fabrics

Wearable electronics and systems with self-powered real-time responses to various stimuli, such as mechanical, electrical, thermal and optical signals，are eagerly desired, however still remain great challenges. Herein, smart fibers with multi-response to external stimuli are developed via wet spinning porous aramid aerogel nanofibers while utilized as a three-dimensional hierarchical percolating skeleton for silver nanowires (AgNWs) interwoven MXene conductive network. The coaxial AgNWs/MXene@ aramid aerogel nanofibers with entangled heterostructures effectively avoid “trade-off” effect between high electrical conductivity and mechanical flexibility of smart fibers. Meanwhile, the hierarchical porous structure of aerogel conductive fibers induced strong capillary force and confinement to polyethylene glycol, which has a wide range of phase transition temperature and huge enthalpy to store tremendous thermal energy. After further encapsulated with transparent fluorosilicone resin, the stabilized smart fiber exhibits excellent self-cleaning properties with water and oil repellent. Furthermore, the woven aerogel fabrics coupled with thermoelectric generator realized efficient reversible energy conversion and storage as well as solar-thermal-electrical power generation for all-weather electricity power supply, which could drive the operation of wearable electronics and car models without batteries, providing an efficient strategy for outdoor travel and lunar rover continuous operating. The smart aramid aerogel fibers and fabrics hold great promise for next generation of self-powered wearable systems.

Hygroscopic ramie fabrics for recovering highly viscous low sulfur fuel oil

Low sulfur fuel oils (LSFOs) with less than 0.5% sulfur content have been mandated for marine vessels by the International Maritime Organization since 2020. However, owing to the low dispersibility and high viscosity of LSFOs, their oceanic spills are difficult to clean using conventional response systems. In this study, we propose a superhydrophilic and hygroscopic ramie to clean spilled LSFO. To this end, a raw ramie fiber, which is intrinsically hydrophobic, was treated using a mild alkali to remove its waxy, rough, and gummy veneer and reveal a smooth surface. This substantially improved its hygroscopic nature, superhydrophilicity, and water-retention, while preserving its mechanical durability in dry and wet environments. The hygroscopic ramie exhibited underwater superoleophobicity and self-cleaning abilities against highly adhesive LSFOs. Two proofs-of-concept are demonstrated in this study—an oil-proof glove for maximizing oil repellency and a direct oil-scooping device for simple and continuous recovery of spilled oil with high efficiency.

Design of poly (arylene ether nitrile)@SiO2 nanoparticles super-wetting membrane for the fast separation of oil-in-water emulsions fabricated through physical confinement effect and dopamine-assisted bio-inspired deposition

The super-wetting polymer-based membrane has displayed promising application in the oily wastewater purification because of its unique anti-fouling feature. However, the creep of micro-/nano- structure on surface of membrane and wettability attenuation under harsh conditions would lead to the decrease of separation flux and efficiency, which posed a huge challenge to the membrane technology. In this study, we prepared the super-hydrophilic and underwater super-oleophobic polymer composite membrane through the one-step biomimetic deposition of sodium alginate, dopamine, and SiO2 nanoparticles onto the surface of poly (aryl ether nitrile) (PEN) membrane with wavy rough structure. Typically, the effect of physical confinement, dopamine with strong adhesion, and the co-deposition of polydopamine and sodium alginate coatings endowed the composite membrane with durable super-wetting property (water contact angle: 0° and underwater oil contact angle: 153°) and oil repellent behavior. Hence, when separating different surfactant-stabilized oil-in-water emulsions, as-prepared PEN composite membrane showed high separation flux of 762.81 ± 28.37 L·m−2·h−1 (847.5 ± 31.52 L·m−2·h−1·bar−1) and rejection ratio of 99.51 ± 0.16 %. Furthermore, the efficient separation performance and super-wetting feature of composite membrane could be retained even treating in the conditions of 4 M HCl/80 ℃ and 1 M NaOH/80 ℃, which exhibited potential application for purification of oily wastewater containing different oil/water emulsions under harsh environments.

Water Efficient, eco-friendly and Effluent Free Nano bubble Finishing of Cotton Fabric

ABSTRACT Existing textile exhaust finishing methods require higher liquor ratios, such as 1:5 and 1:10, leading to energy wastage, chemicals wastage, and higher effluents. However, the nanobubble technique can reduce the liquor ratio to 1:1, resulting in water savings, energy savings, and zero liquid discharge. Nevertheless, production of the nanobubbles for a range of finishes and their successful application onto the textile is a difficult and challenging task. For the first time, this article successfully reports the development and application of nanobubbles at the extremely low liquor ratio of 1:1 for the five most commonly used textile finishes, which include resin, softener, soil release, oil and water repellent, and antimicrobial finishes onto the cotton fabric. In addition, this research compares the performance of the nanobubble finishing at a liquor ratio of 1:1 with higher liquor ratios of 1:5 and 1:10 for all five finishes. The results showed that optimized nanobubble finishing exhibited comparable key performance with reference to liquor ratios of 1:5 and 1:10 related to each finish category. However, the physical properties of cotton fabrics, such as tensile strength, tear strength, bending length, and air permeability, were better for nanobubble technology as compared to conventional finishing.

Eco-friendly Dopamine-Modified Silica Nanoparticles for Oil-Repellent Coatings: Implications for Underwater Self-Cleaning and Antifogging Applications

Solid materials ubiquitously suffer from oil fouling in engineering applications. In this work, a facile and economical method was proposed to prepare a substrate-independent self-cleaning coating with remarkable oil repellency, which were realized by dints of the surface of nanocomposite structures with polar groups introduced by silica nanoparticles and polydopamine. The dip coating preparation process can be carried out in an ambient atmosphere without the use of hazardous reagents or complex equipment. The coating displays self-cleaning performance to detach the adhered oil after being immersed into water. The underwater contact angles were measured over 150° to various oils, further retaining stability in corrosive aqueous environments. Moreover, the coated glass shows resistance to water condensation, which can remain transparent after steaming or frosting, due to its hydrophilicity. The special wettability also endows the coated fabric with permselectivity to water and oil. Modified filter cotton was utilized to separate five kinds of oil/water mixtures. This study proposed a tried-and-true approach to realize oil repellency. It is anticipated that it could set a precedent for the design of self-cleaning or antifouling coatings.

Gelatin-tannic acid coating for high flux oil-water separation

Special wettability material with super-hydrophilicity/underwater super-oleophobicity is one of the best materials for treating oily wastewater, developing an urgent demand for simple, green, low cost, and efficient in practical application. Both gelatin and tannic acid are natural and low-cost renewable resources. In this study, gelatin-tannic acid coating(FOGE-TA) that can be applied to different substrates was prepared by a simple and green dip-coating method using the film-forming properties of gelatin as well as the hydrophobic interactions and hydrogen-bonding interaction between gelatin and tannic acid. The coating can be applied to different substrates such as glass, PP melt-blown nonwoven fabric, copper mesh, and stainless steel mesh. After dipping FOGE-TA, the underwater oil contact angle of the mesh surface all reach over 150 °, and the water contact angle is 0 °. Among them, the prepared gelatin-tannic acid-coated stainless steel mesh(FOGE-TA-4 L-SSM) has a high water flux of over 1.74 × 105 L∙m-2∙h-1 and separation efficiency of over 99.0% for oil/water separation. Due to its excellent oil repellency only needs to be soaked and rinsed with deionized water when the flux decays to continue the oil-water separation. After 90 separations, the water flux and separation efficiency did not significantly decrease. In addition, the FOGE-TA-SSM has good stability in salt solutions and an acidic environment, making it an ideal material for solving oil-water separation problems.

Synthesis of Nontoxic and Bio Based Oil and Water Repellent Polymers for Cotton Fabrics Using Stearic Acid, Succinic Acid, and Itaconic Acid

ABSTRACT Fluorocarbon-based oil and water repellents are considered best in textile finishing due to their excellent performance. Although, long chain fluorocarbons are effective oil and water repellents but they are toxic and being banned. Therefore, the present study develops two fluorine-free water-repelling polymers for cotton fabrics using ecofriendly recipes containing bio-based stearic acid and formaldehyde-free succinic acid and itaconic acid. One optimized recipe was achieved through polymerization between bio-based stearic acid and succinic acid, and other optimized recipe was achieved through polymerization between stearic acid and itaconic acid. These two recipes were applied to cotton fabric, and treated fabric exhibited a water repellency rating of 4 and an oil repellency rating of 1. The proposed polymers exhibited good oil and water repellency and washing durability up to 10 washing cycles. However, after 20 washing cycles, the proposed polymers exhibited water repellency for ironed fabric and zero oil repellency. The proposed polymers exhibited comparable or better testing results than commercial C6-based fluorocarbon. The characterization of the two best recipes was carried out through H-NMR Spectroscopy, scanning electron microscope (SEM), Fourier-transform infrared spectroscopy (FTIR), energy-dispersive X-ray spectroscopy (EDX), and X-ray diffraction (XRD).

Bioinspired Superspreading Surface: From Essential Mechanism to Application.

The dynamic behavior of liquids on surfaces is ubiquitous in nature and has aroused wide attention from researchers. Among them, the superspreading surface has been extensively investigated and applied in areas ranging from film fabrication to antibiofouling, separation, etc. However, the traditional equilibrium contact angle (CA) at the thermodynamic steady-state cannot completely depict the dynamic spreading process of liquids, because the performance of these surfaces is controlled not only by the final steady superhydrophilicity (CA < 5°) but also by the superspreading speed of liquids with a CA of ∼0°. Moreover, as the most basic prerequisite for superspreading, the long-held intrinsic wetting threshold (IWT) of 90°, which divides hydrophobic and hydrophilic surfaces, is also controversial.In this Account, we summarize and condense the commonalities of our related research, further formally propose the concept of "superspreading", and recommend using "superspreading time (ST)" and "curve of superspreading radius versus spreading time (SRST)" to quantify its performance. Learning from nature is the most effective way to artificially fabricate superspreading surfaces. To begin, we first review some typical superspreading surfaces we found in nature and introduce the strategies adopted by the surfaces for surviving or realizing special functions. Then, we systematically review our recent understanding of the essential mechanism of superspreading surfaces across multiple length scales─from the molecular origin of the newly found IWT of ∼65° for water to the macroscopic respective functions of nanostructure and microstructure in superspreading. Armed with the in-depth fundamental mechanism, we propose the designing principle of high-performance superspreading surfaces. Following that, we summarize the commonly utilized methods, including modifying surface composition to give the surface intrinsic hydrophilicity and changing surface structure to improve the superspreading performance. Subsequently, we introduce the recently developed practical applications by virtue of the outstanding property of the superspreading surface, including the fabrication of a self-assembled film on the solid-gas surface and solid-liquid interface, a self-assembled water barrier for antibiofouling and oil repellency, high-efficiency separation and heat dissipation, etc. Finally, we discuss the remaining major challenges and the future development trends in the superspreading field. This Account serves to arouse wide attention and efforts in the superspreading field to strengthen mechanism research and promote practical large-area applications.

Superamphiphobic properties of fluorine doped graphene prepared by RF-PECVD: EIS and first principle study

A fluorine doped graphene (FDG) film was deposited on the surface of roving fabric by radio frequency plasma enhanced chemical vapor deposition (RF-PECVD). The micromorphology, functional group types, chemical composition, molecular structure and nanostructure image of the deposited films under different discharge power were characterized by field emission scanning electron microscope (FE-SEM), Fourier transform infrared spectroscopy (FTIR), X-ray photoelectron spectroscopy (XPS), Raman spectroscopy and transmission electron microscope (TEM). The static and rolling−water/−oil contact angle were measured by contact angle meter. The electrochemistry properties were tested using electrochemical workstation. The superamphiphobic mechanism was studied by electrochemical impedance spectroscopy (EIS) and density functional theory (DFT), and the corresponding software were Gemry Echem Analyst and Materials Studio 7.0, respectively. The results show that the obtained FDG film has the best hydrophobic and oil repellent performance under the discharge power of 80 W. F atom in the FDG film is arranged on both side and the capacitance structure (C-model) is presented in the equivalent element by EIS fitting and DFT calculation under the discharge power of 80 W. The phenomenon proves that the electron transfer of free electrons from the position of K point in the Brillouin region of graphene surface was forbidden by the F atom, which is the mechanism of superhydrophobic and oil drainage on the FDG film surface.

Slippery, Water‐Infused Membrane with Grooved Nanotrichomes for Lubricating‐Induced Oil Repellency (Adv. Sci. 13/2022)

Slippery Water Infused Membrane with Grooved Nanotrichomes Sarracenia leucophylla, a carnivorous pitcher plant, has short trichomes covering the inner wall. When wet by water, the trichomes help to form a water-based lubrication layer, which becomes slippery for the prey insects to slip into a pitfall trap. In article number 2103950, Young A Lee, Seok Chung, Myoung-Woon Moon, and co-workers, inspired by the water lubrication, develop a slippery, water-infused membrane with grooved nanotrichomes for lubricating-induced oil repellency and self-cleaning in air or underwater.

Mussels-inspired design a carbon nanotube based underwater superoleophobic/hydrophobic Janus membrane with robust anti-oil-fouling for direct contact membrane distillation

Membrane distillation is an emerging technique effective in desalination and other membrane separation processes. However, hydrophobic membrane fouling caused by non-polar foulants limits the practical oily wastewater application. In this study, an underwater-super-oleophobic/hydrophobic Janus membrane with flux enhancement and robust anti-oil-fouling property was fabricated through formation of a carbon nanotube/PDA/PEI hydrophilic surface coating on a PVDF membrane. The process comprised construction of carbon nanotube layer and bioinspired-adhesive polydopamine/Polyethyleneimine (PDA/PEI) which enhanced hydrophilicity and stability of the membrane. Integration of the hydrophilic property of PDA/PEI and the multiscale structures of CNT endowed the membrane with air-hydrophilicity, underwater superoleophobicity and anti-oil-fouling properties. Introduction of CNT increased the mass and heat conduction performance of the membrane, which was attributed to increased flux. Use of PDA/PEI firmly fixed the carbon nanotube layer on the membrane surface and effectively increased hydrophilicity of the membrane surface. Increase in hydrophilicity resulted in improved underwater-superoleophobicity of the modified membrane. The anti-oil-fouling properties of the Janus membrane were explored by treatment with saline feed containing 1000 mg L−1 mineral oil. The Janus membrane showed an excellent enhanced flux and oil repellent during the test. Our study provides an ideal strategy to tailor Janus membrane with excellent surface wettability for oily wastewater treatment.

Non-Fluorine Oil Repellency: How Low the Intrinsic Wetting Threshold Can Be for Roughness-Induced Contact Angle Amplification?

Surface chemistries for realizing oil repellency are mostly based on perfluoro compounds (PFCs) owing to their low surface energy. However, PFCs are not sustainable because of their persistent and bioaccumulative properties, and their usage, even short-chain ones, has begun to be phased out. To date, studies on non-fluorine oil repellency have been extremely rare, and the obtained oil repellency has been limited. Here, we report the non-fluorine oil repellency of a coating prepared on a tightly woven plain-weave fabric through hydrolysis and polycondensation of difunctional chlorosilane. The coated fabric exhibited a contact angle of 119.0° for castor oil and 81.4° for hexadecane, as well as a contact angle of 51.9° for decane with a surface tension as low as γLV = 23.5 mN m-1. According to the standard ISO 14419:2010, oil repellency was rated Grade 6. The solid surface tension of the coating was calculated to be γSV = 22.1 mN m-1. Through the test of the difference in contact angles between rough and smooth surfaces, the intrinsic wetting threshold (θIWT) for such a surface chemistry was determined to be ranging from 8.9 to 14.5°. A study on the effects of surface morphologies suggests that the realization of an oil-repellency rating of 6 and a θIWT as low as 8.9-14.5° strongly depends on the roughness topographies. We hope that this study will be useful for the design─and our understanding─of non-fluorine oil repellency for applications including stain-resistant textiles and grease-resistant food packaging.

Improvement of Oil and Water Barrier Properties of Food Packaging Paper by Coating with Microcrystalline Wax Emulsion.

Studies have shown that fluorinated oil repellents are potentially harmful to humans and the environment, and therefore, the development of non-toxic, green, and environmentally friendly oil repellents has become inevitable. Microcrystalline wax is a branched saturated alkane with a molecular weight of 580–700 Da, which has a lower surface tension than edible oil. Herein, microcrystalline wax emulsion (fluorine-free oil repellent) was prepared by mechanical stirring–homogenization, the effects of emulsifier ratio and dosage on the emulsion performance were systematically investigated, and the resultant stable microcrystalline wax emulsions were applied to the paper surface to explore the oil and water resistance and water vapor barrier performance. The results showed that stabilized microcrystalline wax emulsion was obtained at the emulsifier Span-80/Tween-80 ratio of 5:5, and the emulsifier dosage was 20% (relative to the microcrystalline wax). When 6 g/m2 of microcrystalline wax was applied to the surface of starch pretreated paper, the kit rating value of the paper was high, at up to 10/12, the Cobb60 value decreased to 12.5 g/m2, the overall migration of paper was less than 10 mg/dm2, and the water vapor permeability was reduced by 81.9%, which met the requirements of oil and water resistance performance of food packaging paper.