Dodecafluoroheptyl Methacrylate Research Articles

Fabrication of core-shell polyacrylate latex pressure sensitive adhesives modified by fluorinated monomer and film properties

In this work, a series of fluorinated core-shell polyacrylate latex pressure sensitive adhesives (PSAs) were successfully synthesized through monomer-starved seeded semi-continuous emulsion polymerization. Specifically, (meth)acrylate monomers were employed as the main materials, with dodecafluoroheptyl methacrylate (DFMA) were used as modified monomer. The impact of fluorine monomer DFMA on the resulting core-shell latex and PSA properties was thoroughly examined. FTIR analysis confirmed the successful incorporation of DFMA into the latex copolymer through emulsion polymerization. TEM images illustrated that the morphology of latex particles exhibit a distinct core-shell structure. The results also showed that with the addition of DFMA, the water absorption and water whitening of the latex films decreased, while the water contact angle and thermal stability are improved. Interestingly, the latex films with DFMA added to the shell phase exhibit a larger WCA value when compared to those with DFMA in the core phase, further confirmed by XPS results. Finally, the adhesive properties of the fluorinated core-shell acrylate PSA were evaluated. The results of shear strength and gel content demonstrate that the prepared PSA exhibits excellent cohesive properties. Thus, this work could present a feasible strategy for optimizing the comprehensive properties of acrylate latex PSAs.

Hierarchical nanoengineered emulsion with robust adhesion enables superior self-cleaning cotton fabrics

Self-cleaning treatment is of vital importance for the practical application of functional cotton fabrics. However, developing highly efficient, eco-friendly, and durable hydrophobic and oleophobic treatment agents still remains a great challenge. Herein, inspired by the design of the inorganic–organic nanonetwork, we successfully synthesized a novel core–shell structured emulsion of nano-SiO2/fluorine-silicon polyacrylate through semi-continuous emulsion polymerization. The introduction of long-chain alkyl methacrylate octadecyl ester within the shell phase results in a more organized arrangement of fluorine atoms on the surface of cotton fabrics, leading to a rapid reduction in the surface free energy of latex film. The sample is optimized with 20 wt% dodecafluoroheptyl methacrylate and 1 wt% SiO2. The nanoengineered emulsion exhibits strong adhesion and effectively transforms the hydrophilic cotton fabrics into hydrophobic (143.2°) and oleophobic (121.6°) materials. Besides, the self-cleaning characteristic can withstand 25 laundering cycles and 800 abrasion cycles with enhanced robustness. This work opens up a pathway to develop effective, green but long-lasting amphiphobic agents for functional fabrics and sustainable textiles.

Research on Nano-ZnO/fluorine Polyacrylate Linen Fabric Finishing Agent

ABSTRACT With nano-ZnO, methyl methacrylate (MMA), ethyl acrylate (EA), and dodecafluoroheptyl methacrylate (DFMA) as reaction monomers, potassium persulfate as initiator, nano-ZnO/fluorine polyacrylate linen fabric finishing agent was prepared by semi-continuous seed emulsion polymerization to improve the hydrophobicity and anti-fouling performance of linen fabric. The structure and properties of the film and the finished fabric were characterized and analyzed by1HNMR, FT-IR, and TG. The results showed that the nano-ZnO/fluorine emulsion was successfully prepared with a particle size of about 46 nm, which was combined with linen. The contact angle of the finished linen fabric to water was 130.33°, which indicated that the finished linen fabric had good hydrophobicity. Meanwhile, the anti-fouling performance of the finished linen fabric was also improved. The introduction of nano-ZnO and organic fluorine in turn made linen fabric had the properties of the heat-resistant stability, UV resistance, antibacterial properties, and yellowing resistance.

Synthesis and Properties of Cationic Core-Shell Fluorinated Polyurethane Acrylate.

Vinyl-capped cationic waterborne polyurethane (CWPU) was prepared using isophorone diisocyanate (IPDI), polycarbonate diol (PCDL), N-methyldiethanolamine (MDEA), and trimethylolpropane (TMP) as raw materials and hydroxyethyl methacrylate (HEMA) as a capping agent. Then, a crosslinked FPUA composite emulsion with polyurethane (PU) as the shell and fluorinated acrylate (PA) as the core was prepared by core-shell emulsion polymerization with CWPU as the seed emulsion, together with dodecafluoroheptyl methacrylate (DFMA), diacetone acrylamide (DAAM), and methyl methacrylate (MMA). The effects of the core-shell ratio of PA/PU on the surface properties, mechanical properties, and heat resistance of FPUA emulsions and films were investigated. The results showed that when w(PA) = 30~50%, the stability of FPUA emulsion was the highest, and the particles showed a core-shell structure with bright and dark intersections under TEM. When w(PA) = 30%, the tensile strength reached 23.35 ± 0.08 MPa. When w(PA) = 50%, the fluorine content on the surface of the coating film was 14.75% and the contact angle was as high as 98.5°, which showed good hydrophobicity; the surface flatness of the film was observed under AFM. It is found that the tensile strength of the film increases and then decreases with the increase in the core-shell ratio and the heat resistance of the FPUA film is gradually increased. The FPUA film has excellent properties such as good impact resistance, high flexibility, high adhesion, and corrosion resistance.

Synthesis and performance of novel fluoro acrylate polymer containing rigid cyclohexane group as a mesogenic core

Fluorine-containing liquid crystal polymers have excellent hydrophobic stability, making them attractive for use in the field of stable hydrophobic coatings. To improve the hydrophobic stability of fluoropolymers, a novel fluoro acrylate monomer (FAM) containing a rigid cyclohexane structure was simply synthesized using isophorone diisocyanate (IPDI), hydroxyethyl methacrylate (HEMA), and perfluorohexylethanol (S104) as raw materials and its homopolymer (PFAM) was prepared by radical solution polymerization. The structure, liquid crystal behavior, thermal properties, hydrophobic properties, and surface properties of FAM or PFAM and a reference substance, dodecafluoroheptyl methacrylate (DFMA) and its homopolymer (PDFMA), were studied using various techniques including FT-IR, NMR, GPC, XRD, POM, DSC, TGA, XPS, AFM, and static/dynamic contact angle measurements. The results indicate that FAM and PFAM are thermally liquid crystalline. PFAM's thermal stability is higher than that of PDFMA. The presence of a rigid cyclohexane structure facilitates the dense distribution of fluorocarbon chain tails of the homopolymer and also prevents surface reconstruction when the homopolymer comes into contact with polar liquids, resulting in improved hydrophobicity and hydrophobic stability. Thus, this study provides a straightforward method for the synthesis of fluoro acrylates with surface stability, highlighting their potential application in hydrophobic coatings.

Facile UV-Induced Surface Covalent Modification to Fabricate Durable Superhydrophobic Fabric for Efficient Oil-Water Separation.

In this work, a durable superhydrophobic fabric was fabricated by using a facile UV-induced surface covalent modification strategy. 2-isocyanatoethylmethacrylate (IEM) containing isocyanate groups can react with the pre-treated hydroxylated fabric, producing IEM molecules covalently grafted onto the fabric's surface, and the double bonds of IEM and dodecafluoroheptyl methacrylate (DFMA) underwent a photo-initiated coupling reaction under UV light radiation, resulting in the DFMA molecules further grafting onto the fabric's surface. The Fourier transform infrared, X-ray photoelectron spectroscopy and scanning electron microscopy results revealed that both IEM and DFMA were covalently grafted onto the fabric's surface. The formed rough structure and grafted low-surface-energy substance contributed to the excellent superhydrophobicity (water contact angle of ~162°) of the resultant modified fabric. Notably, such a superhydrophobic fabric can be used for efficient oil-water separation, for example a high separation efficiency of over 98%. More importantly, the modified fabric exhibited excellent durable superhydrophobicity in harsh conditions such as immersion in organic solvents for 72 h, an acidic or alkali solution (pH = 1-12) for 48 h, undergoing laundry washing for 3 h, exposure to extreme temperatures (from -196° to 120°), as well as damage such as 100 cycles of tape-peeling and a 100-cycle abrasion test; the water contact angle only slightly decreased from ~162° to 155°. This was attributed to the IEM and DFMA molecules grated onto the fabric through stable covalent interactions, which could be accomplished using the facile strategy, where the alcoholysis of isocyanate and the grafting of DFMA via click coupling chemistry were integrated into one-step. Therefore, this work provides a facile one-step surface modification strategy for preparing durable superhydrophobic fabric, which is promising for efficient oil-water separation.

Preparation and Properties of Hydrophobic and Oleophobic Coating for Inkjet Printing

As a functional decorative material on the surface of printing and packaging, coating plays the role of increasing gloss, wear resistance, and antifouling. It has broad application prospects in high-end printed materials such as posters, art reproductions, and maps. In this paper, dodecafluoroheptyl methacrylate was used as the fluorine-containing monomer, which was used to modify the epoxy resin and introduce fluoride first. Under the action of polymerization inhibitor and catalyst, the epoxy resin was further modified by ring opening, esterification, and neutralization with acrylic acid, maleic anhydride, and organic base as raw materials. Additionally, a fluorine-containing coating with hydrophobic and oleophobic properties was obtained finally. The effects of fluorine modification of epoxy resin and synthetic polymer were characterized by infrared spectrometer and photoelectron spectroscopy. The results showed that fluorine monomer could be successfully grafted to the molecular body of epoxy resin, and fluorine had been introduced into the surface of the polymer film. Using the contact angle tester, combined with the performance parameters such as grafting rate, thermal stability, adhesion, and gloss, the effects of the amount of fluorine monomer on the properties of the synthetic coating were discussed. The results showed that the hydrophobic and oleophobic properties of the copolymer film surface were closely related to the amount of fluorine monomer. When the molar ratio of the epoxy group to dodecafluoroheptyl methacrylate was 26:1, the mass fraction of fluorine on the film surface was 18.09%, and the contact angles of water and ethylene glycol were 121.8° and 78.2° respectively. At the same time, the printability of self-made hydrophobic and oleophobic coating was tested in this paper. The liquid repellency of inkjet printing before and after glazing and the influence of the coating on the optical properties of printed images were discussed and studied too. The results showed that the coating synthesized by the experiment was suitable for inkjet printing. It had improved the printing quality performance and the functional modification on the surface of inkjet printings, such as liquid repellency, gloss, and color reproduction.

Preparation and Performance of Cotton Fabric with Antibacterial and Hydrophobic Properties Based on Click Reaction

A simple modification method for creating cotton fabrics with hydrophobic and antibacterial surface properties is proposed. Silicon dioxide nanoparticles were obtained and added to a mixed solution of ethanol and silver nitrate to form a composite solution, and the SiO2/Ag+ composite solution was used to modify the cotton fabric. Then, the fabric was modified by self-assembly of (3-mercaptopropyl) triethoxysilane (MPTES), and the modified fabric was completed by grafting dodecafluoroheptyl methacrylate using click chemistry technology. A scanning electron microscope (SEM), Fourier transform infrared spectrometer (FTIR), thermogravimetric/differential thermal analyzer (TG), and contact angle measuring instruments were used to characterize the surface morphology and wettability of the cotton fabric. The results showed that the modified cotton fabric had a contact angle of 114.3 ° and still had good hydrophobicity after being subjected to multiple frictions. The modified cotton fabric also showed good antibacterial properties against Escherichia coli (E. coli) in a Petri dish.

Synthesis and Characterization of a Coumarin Antimicrobial Polymer Fluorescent Coating

Polymer materials are widely used in medical materials, food packaging, coatings, and other fields. However, the surface of the materials is easily contaminated by microorganisms, resulting in serious problems. To solve this issue, a new type of antibacterial polymer fluorescent coating was successfully synthesized by copolymerization of divinylbenzene with 7-methacryloxy-4-methyl coumarin, dodecafluoroheptyl methacrylate, and other monomers. The surface structure and thermal stability of the coating were characterized by Fourier transform infrared spectroscopy, scanning electron microscopy, and thermogravimetric analysis. Fluorine was polymerized into the polymer, improving the thermal stability compared to polystyrene and polydivinylbenzene. The bactericidal and antibacterial adhesion properties of the coating materials were studied by a contact germicidal test and antibacterial adhesion test. The polymer had a strong inhibitory effect on Staphylococcus aureus. After immersion in room temperature water, the film maintained its strong inhibitory effect on S. aureus fluorescence intensity and had high fluorescence stability.

Study on preparation and performance of multifunctional linen fabric finishing agent

The research in textiles is being driven by economy and functionality. Therefore, the present research is focused on the development of multifunctional textiles with simple process. Herein, a highly efficient multifunctional linen fabric finishing agent was developed with nano-ZnO, dodecafluoroheptyl methacrylate, vinyl trimethoxysilane, methyl methacrylate, and butyl acrylate as raw materials. The finishing agent imparted linen fabric multiple performance characteristics such as hydrophobic, antibacterial and ultraviolet protection. Infrared spectroscopy analysis, particle size test and transmission electron microscopy were used to analyze the main characteristics of multifunctional linen fabric finishing agent, including the main groups, particle size distribution and particle morphology. The results showed that the nano-ZnO/fluorosilicone-polyacrylate emulsion finishing agent had been successfully prepared, and the finishing agent had good stability. By means of scanning electron microscopy, thermogravimetry, and X-ray diffractometry, it was found that the finishing agent successfully covered the surface of the linen fabric, which increased the thermal decomposition temperature of the linen fabric and reduced the crystallinity of the linen fabric, indicating that improved the heat stability and softness of the fabric. Similarly, the application performance of linen fabric was tested. Compared with the original linen fabric, the finished linen fabric had good ultraviolet protection, antibacterial, hydrophobicity, washing fastness and breaking strength, leading to the improvement of the wear performance of linen fabric. Thus, the multifunctional linen fabric finishing agent has the advantages of simple technology, low cost and promising prospect.

Fabrication of Durable, Chemically Stable, Self-Healing Superhydrophobic Fabrics Utilizing Gellable Fluorinated Block Copolymer for Multifunctional Applications.

Limited durability and complex materials restrict the application of superhydrophobic fabrics in daily life. In this work, gellable fluorinated block copolymer poly(dodecafluoroheptyl methacrylate)-block-poly(3-(triethoxysilyl)propyl methacrylate) (PDFMA-b-PTEPM) was used to fabricate adhesive-free superhydrophobic poly(ethylene terephthalate) (PET) fabrics via a simple dip-coating technology and sol-gel reaction. The growth of silica nanoparticles builds up a rough hierarchical structure and provides sol-gel reaction sites of PTEPM segments. The grafting of block copolymer significantly reduced the surface free energy of the fabrics, resulting in an excellent superhydrophobicity with a water contact angle of 160.2°. Benefiting from extensive chemical bond grafting and cross-linking of the PTEPM segment, the fabric exhibits excellent durability in mechanical abrasion, chemical treatment, and washing. The coating has withstood 50 sandpaper abrasion cycles and 400 soft friction cycles and can maintain superhydrophobic properties in various solvents, freezing and a wide pH range. These superhydrophobic fabrics with a long life span possess self-cleaning, anti-icing, oil-water separation, and self-healing capabilities. The multifunctional fabrics developed in this study are durable and easy to produce, possessing the potential for applications in industry and daily life.

The Synergistic Effect of Terminal and Pendant Fluoroalkyl Segments on Properties of Polyurethane Latex and Its Film

The hydrophobic modification effect and an appropriate cost of waterborne polyurethane are regularly pursued targets of researchers. To further enhance the hydrophobic modification effect of the terminal fluoroalkyl group and control the cost, a fluorine-containing pendant group diol (DEFA) was first synthesized by the Michael addition reaction of diethanolamine (DEOA) and dodecafluoroheptyl methacrylate (G04). Next, a series of modified polyurethane latexes (TPFPU) by the terminal fluoroalkyl segments (perfluorohexyl ethanol, S104) and the pendant fluoroalkyl segments (DEFA) were synthesized by varying the DEFA dosage. Structure and performance properties of the resultants were characterized by IR, 1H NMR, TEM, TGA, DSC, XRD, XPS, SEM, AFM and contact angle measurements. Results confirmed that the product could be successfully prepared using the present method. With the increase in DEFA dosage, the average particle size increased gradually. Thermal stability was enhanced and small regional crystals were probably produced. XPS and AFM results demonstrated that the degree of microphase separation and film roughness were increased with the increase in DEFA amount. Hydrophobicity of the TPFPU’s film was also increased with the increase in DEFA dosage, and it could be guaranteed when the mass content of S104 and DEFA was larger than 17.0 wt% in total mass of raw materials, which demonstrates that the terminal and pendant fluoroalkyl groups have the favorable synergistic effect on the properties of polyurethane.

Superhydrophobic fluorinated microspheres for fluorous affinity chromatography

Fluorous affinity chromatography has received growing attention in separation and purification of fluoro compounds, but the wettability of the fluorinated stationary phases is seldom noticed. Here, we construct a series of micro-sized fluorine-containing microspheres by solvothermal precipitation polymerization. The fluorinated microspheres could be obtained with narrow size distribution at even high monomer loading of 15 wt%. Through alternating fluoro monomer, both the particle size and the wettability of the microsphere array could be tuned. Among them, the poly(divinylbenzene -dodecafluoroheptyl methacrylate), P(DVB-DFHMA), microsphere (6.1 μm) arrays displays superhydrophobicity with 153.2° water contact angle. The P(DVB-DFHMA) fluorinated microspheres (7.58% fluorine content) can be packed into steel-less columns as stationary phase for high-performance liquid chromatography. The retention mechanism of the fluorinated column is proven to be the specific fluorine-fluorine interaction. Compared to the commercial C18 silica column, the fluorinated column can completely separate fluorine-containing compounds under high water content mobile phase, including small fluoro molecules and fluoro macromolecules, at much lower back pressure by fluorous affinity.

Comparative study on cross-linked fluorocarbon acrylate latex

PurposeSelf-crosslinked long fluorocarbon acrylate polymer latex has good hydrophobic and oleophobicity, weather resistance, aging resistance, stability and other excellent properties, which make the polymer be widely used in coatings, dyes, adhesives and other products. The purpose of this study is to prepare self-crosslinked long fluorocarbon acrylate polymer latex via semi-continuous seeded emulsion technology and carry out comparative study on two different cross-linked monomers.Design/methodology/approachMethyl methacrylate (MMA) and butyl acrylate (BA) were used as the main monomers, dodecafluoroheptyl methacrylate (DFMA) as the fluoromonomer, hydroxypropyl methacrylate (HPMA) and N-methylol acrylamide (NMA) as cross-linked monomers, and 1-allyloxy-3–(4-nonylphenol)-2-propanol polyoxyethylene (10) ether (ANPEO10) and 1-allyloxy-3–(4-nonylphenol)-2-propanol polyoxyethylene (10) ether ammonium sulfate (DNS-86) as compound emulsifiers via the semicontinuous-seeded emulsion polymerization.FindingsThe properties of the polymer emulsions, which are prepared with two different cross-linked monomers, are compared and discussed, and it is concluded that HPMA is more suitable for the preparation of self-crosslinked polymer emulsions. The formula of the polymer latex is ANPEO10: DNS-86 = 1:1, and the mass ratio of the monomers used in the polymer is MMA: BA: DFMA: HPMA = 14.40:14.40:0.60:0.60.Practical implicationsSelf-crosslinked long fluorocarbon acrylate polymer latex can be used in many fields such as coatings, dyes, adhesives and other products.Originality/valueThe self-crosslinked long fluorocarbon acrylate polymer latex is prepared by mixing the nonionic emulsifier ANPEO10 and the anionic emulsifier DNS-86 when potassium persulfate is used as the thermal decomposition initiator and the semicontinuous-seeded emulsion technology is adopted and the comparative study on two different cross-linked monomer is carried out, which is not reported in the open literatures.

A PECVD fabricated ultra-thin bilayer coating with superior corrosion resistance and low signal loss for high-frequency PCBs

Undesirable high thickness, terrible loss of high-frequency signal and poor adhesion of the traditional coating had plagued the anticorrosive field of high-frequency circuit boards (PCBs). Herein, a novel ultra-thin bilayer anticorrosive coating was manufactured. The initial Poly (butyl acrylate) coating (~30 nm) was firstly fabricated on the PCBs by plasma enhanced chemical vapor deposition (PECVD). Immediately, the Poly (dodecafluoroheptyl methacrylate) coating, as an external protective coating with low surface energy, was fabricated onto the initial Poly (butyl acrylate) coating via a similar approach. The bilayer anticorrosive coating showed the convex structure of bionic lotus leaf, which caused the water contact angle raised from 62.3° to 108.7°. After a 96-hour corrosion test, the circuit of the high-frequency PCBs with the coating (only 250 nm) can be perfectly protected. Simultaneously, the cross-cut test and molecular dynamics simulations showed the coating had an excellent interface adhesion with the PCB substrate. Importantly, compared with the commercial coating, the bilayer anticorrosive coating exhibited little signal loss over a wide frequency range, even up to 0.63 dB (250 nm, 20 GHz). This work provided clear guidance and a strong impetus for the development of corrosion-resistant coating for high-frequency PCBs.

Nano‐silica/fluorinated polyacrylate composites as surface protective coatings for simulated stone cultural relic protection

AbstractStone cultural relics are widely distributed globally and have significant historical and cultural significance and research value. However, most of them have suffered severe weathering and erosion due to the physical and chemical effects of different climatic conditions. Herein, a series of nano‐silica/fluorinated polyacrylate composites as surface protective coatings to protect simulated stone cultural relics were prepared with dodecafluoroheptyl methacrylate (DFMA), acrylates, and different contents of nano‐silica. The storage stability, mechanical stability, coagulum rate, and surface tension of the composite coatings were measured. The UV absorption, chemical structure, surface morphology, and thermal properties of composite films were characterized. When the nano‐silica content was 6 wt%, the optimal nano‐silica/fluorinated polyacrylate (Si‐F‐3) composite with excellent comprehensive properties was applied in the protection of simulated stone cultural relics. Compared with the uncoated original stone samples, the simulated stone cultural relics treated with Si‐F‐3 composite not only had freeze–thaw resistance but also could slow down sulfate erosion and freeze–thaw coupling cycle (SEFTCC) test damage. To conclude, the nano‐silica/fluorinated polyacrylate composites could be a desirable solution for protecting stone cultural relics.

Synthesis of Trivinylisooctyl POSS and Its Application in UV-Curing of Polyurethane Acrylate Coatings

To improve the overall performance of polyurethane acrylic (PUAs) coatings applied to an iron or wood substrate, a modifier, trivinylisooctyl polyhedral oligomeric silsesquioxane (TVi7iso–POSS), was successfully synthesized by a polycondensation reaction in the presence of an organotin catalyst. TVi7iso–POSS is a POSS derivative possessing three olefin and seven isooctyl bonds; its molecular structure was confirmed by FT-IR, 1H-NMR, and mass spectrometry. The synthesized TVi7iso–POSS was then used as a modifier with butyl methacrylate (BMA), dodecafluoroheptyl methacrylate (DFMA), difunctional PUA (PUA–2), and photo-initiator 1173 to produce a novel polyurethane coating (PFMPUAs) via UV-curing. The performance of the obtained PFMPUAs coating was analyzed via X-ray photoelectron spectrometry, SEM, atomic force microscopy, TGA, and differential scanning calorimetry. The newly synthesized modifier, TVi7iso–POSS, enhanced the thermal stability, hardness, flexibility, impact resistance, and adhesion of the PUAs coating and maintained its good light transmittance. Moreover, the PFMPUAs coating exhibited better overall performance compared to the previously studied PUAs coating when the addition of TVi7iso–POSS and DFMA was 15 wt.% of PUA–2. Therefore, the PFMPUAs coating has potential applications in the field of environmentally friendly coatings.

Study on preparing of diallyl maleate modified acrylic resin

PurposeThere are three double bonds in the chemical structure of diallyl maleate. The purpose of this study is that the acrylate is modified with diallyl maleic anhydride to make the propionate resin present a spatial network structure, thereby improving the performance of the acrylate resin.Design/methodology/approachMethyl methacrylate (MMA) and butyl acrylate(BA) were used as were used as main monomers. Diallyl maleate (DAM) was used as crosslinking monomer and dodecafluoroheptyl methacrylate (DFMA) was used as fluoromonomer. Potassium persulfate (KPS) was used as thermal decomposition initiator, sodium lauryl sulfate (AS) and sodium dodecyl sulfonate (SDS) were used as anionic emulsifiers, and EFS-470 (Alkyl alcohol polyether type nonionic emulsifier) was a non-ionic emulsifier.FindingsThrough optimizing the reaction conditions, the uniform and stable latex is obtained. The polymer of structure was characterized by Fourier transform infrared spectroscopy (FTIR). Thermogravimetric analysis (TGA) and contact angle (CA) were tested on latex films. The particle size and distribution range of emulsion were tested with nano particle size analyzer.Originality/valueThe experimental results showed that the thermal decomposition temperature of the acrylic coating film increased by 20.56°C after modification. In addition, the effect of cross-linking density on the water contact angle of the fluorocarbon groups in DFMA when they migrate to the surface of the latex film during drying has been explored. The experimental results show that a higher degree of cross-linking will hinder the migration of fluorocarbon groups to the surface of the resin film.

Fabrication and performance of a superhydrophobic fluorine-modified porous silicon based on photocatalytic hydrosilylation

Porous silicon was widely used in displays, optical sensors, and biological imaging due to its high surface areas, adjustable microstructure, large adsorption capacity and excellent optical performance. Unfortunately, there are numerous reactive silane groups on the freshly etched porous silicon surface, which are susceptible to oxidization in the air, thereby affecting the optical performance and stability of porous silicon. This study provides an efficient strategy of using photocatalytic reaction to graft dodecafluoroheptyl methacrylate to freshly prepared n-type porous silicon surface, thereby generating a fluorine-modified porous silicon with high stability and superhydrophobic surface. The structure and composition of porous silicon before and after modification were analyzed by scanning electron microscope (SEM), Fourier transform infrared spectroscopy (FT-IR), scanning electron microscopy-energy dispersive spectrometer (SEM-EDS) and X-ray photoelectron spectroscopy (XPS). The effects of UV light, reactant mass fraction and reaction time on the surface properties of porous silicon were studied by water contact angle (WCA) and photoluminescence (PL). The results indicated that the dodecafluoroheptyl methacrylate was successfully grafted onto n-type porous silicon surface by photocatalytic reaction. The superhydrophobic and luminescent porous silicon was prepared by reacting 40 min in a dichloride solution containing 10 wt% dodecafluoroheptyl methacrylate under UV light. The WCA of the fluorine-modified porous silicon surface could reach 153° and had good photoluminescence intensity. This modified porous silicon surface had great stability in alkaline and air environment. After treated with alkaline droplets for 30 min, the WCA of modified porous silicon could maintain above 150° and had good photoluminescence. And under room temperature within a week, the porous silicon surface still showed great hydrophobic properties and photoluminescence intensity. In addition, the modified porous silicon has different responsiveness to ethanol solutions of different concentrations, which could be applied to alcohol sensors and has great development prospects. • A fluorine-modified porous silicon was synthesized by a simple and efficient photocatalytic reaction. • The WCA of the fluorine-modified porous silicon surface could reach 153°. • The photoluminescence intensity showed a great stability in alkaline and air environment.

Enhancing anti-corrosion property of novolac vinyl ester coatings on mild steel through introduction of fluoric acrylic monomer and β-Si3N4 nanoparticles

Novolac vinyl ester (NVER) often serves as film-forming material in severe corrosion environment. Unfortunately, major hydrophilic groups gathering on the surface and voids are produced in the solidifying process, which is an intrinsic defect. In order to fulfill the hydrophobicity and promote antiseptic performance, the fluorinated NVER coatings (F-NVERs) was modified with dodecafluoroheptyl methacrylate (DFHMA) by chain polymerization reaction and different loading ratio of β-Si3N4 nanoparticles was introduced to the polymeric matrix through ultrasound approach to fabricate DFHMA modified NVER-based nanocomposite coatings (S/F-NVERs) protection system. The chemical structure, hydrophobicity and morphology were examined by Fourier-transform spectroscopy, contact angle measurement and scanning electron microscope, respectively. Moreover, the corrosion barrier property of coatings on mild steel was also evaluated through immersion and electrochemical impedance spectroscopy. According to the findings, the nanocomposite coatings prepared via addition of 8 wt% DFHMA and 3 wt% β-Si3N4 were confirmed with decent hydrophobicity and optimal corrosion protection ability. Also, the effect of dispersity on corrosion resistance, among disparate addition of β-Si3N4, was systematically discussed.