Preparation and applications of novel fluoroalkyl end‐capped vinyltrimethoxysilane oligomer/hydroxyapatite nanocomposites

Novel fluoroalkyl end‐capped vinyltrimethoxysilane oligomer/hydroxyapatite (HAp) nanocomposites were prepared by the reaction of calcium nitrate tetrahydrate and phosphoric acid in the presence of the corresponding oligomer. These fluorinated oligomer/HAp composites thus obtained are nanometer size‐controlled fine particles (83–173 nm), and were found to exhibit good dispersibility in methanol, ethanol, and isopropyl alcohol. These fluorinated HAp nanocomposites were applied to the surface modification of glass and poly(methyl methacrylate) (PMMA) to exhibit good hydro‐ and oleophobic characteristics imparted by fluorine on their surface. In addition, the surface structural changes of the modified polyethylene terephtalate and PMMA films treated with these fluorinated nanocomposites before and after soaking in a simulated body fluid (SBF) were analyzed by using SEM, XRD, and EDX to observe the formation of spherical HAp deposits on the surface. Copyright © 2009 John Wiley & Sons, Ltd.     

不同润湿性锡青铜表面摩擦特性实验研究

运用微细掩膜脉冲电解加工在锡青铜表面制备了不同直径和面积率的微结构,并辅以低表面能处理得到了不同润湿性表面;采用接触角测量仪表征了润滑油的润湿性能;使用球-盘式摩擦磨损试验机研究了油润滑时不同润湿性锡青铜表面的摩擦学特性,并采用扫描电镜观察表面磨损形貌.研究结果表明:低表面能处理后的结构化试样具备疏油性,且其疏油性随着微结构密度增加而增加;与未经润湿性处理表面相比,低润湿性光滑表面和结构化表面摩擦系数最大降幅分别为21.2%、33.6%,磨损率降幅分别为17.3%、4.9%;在3 N载荷、球-面接触副条件下,所制备的4种不同直径微结构中,微结构直径小于30μm时,面积率为4.9%或当直径大于等于30μm时,面积率为8.7%的低润湿性表面减摩效果最好.     

Fluoroalkyl end‐capped oligomers possessing nonflammable characteristic in calcium carbonate nanocomposites

Calcium chloride reacted with sodium carbonate in the presence of a variety of fluoroalkyl end‐capped oligomers such as fluoroalkyl end‐capped acrylic acid oligomer (R_F‐[ACA]_n‐R_F), 2‐methacryloyloxyethanesulfonic acid oligomer (R_F‐[MES]_n‐R_F), N,N‐dimethylacrylamide oligomer (R_F‐[DMAA]_n‐R_F) and acryloylmorpholine oligomer (R_F‐[ACMO]_n‐R_F) to afford the corresponding fluorinated oligomers/calcium carbonate composites. Each fluorinated oligomer/calcium carbonate composite thus obtained is nanometer size‐controlled very fine particles (25–114 nm) possessing a good dispersibility and stability in a variety of solvents including water. Thermal stability of these fluorinated calcium carbonate nanocomposites was studied by thermogravimetic analyses measurements. Fluorinated oligomes, in which the theoretical oligomer content in the composites is 19%, were able to give no weight loss corresponding to the content of oligomer in each case even after calcination at 800 °C. On the other hand, a slight weight loss corresponding to the contents of oligomers in the composites after calcination at 800 °C was observed in R_F‐(MES)_n‐R_F/, R_F‐(DMAA)_n‐R_F/ and R_F‐(ACMO)_n‐R_F/calcium carbonate nanocomposites, in which the theoretical contents of the oligomers were 36–53%, although R_F‐(ACA)_n‐R_F/calcium carbonate nanocomposites gave a clear weight loss corresponding to the contents of oligomer under similar conditions. Fluorinated oligomers/calcium carbonate nanocomposites possessing no weight loss at 800 °C were applied to the surface modification of poly(methyl methacrylate) (PMMA) to exhibit a good oleophobicity imparted by fluorines on the surfaces. Interestingly, these fluorinated calcium carbonate nanocomposites after calcination at 800 °C were found to exhibit the similar oleophobic characteristic on the modified PMMA surfaces as well as that of the nanocomposites before calcination. Copyright © 2013 John Wiley & Sons, Ltd.     

含氟丙烯酸酯共聚物结晶性与涂膜表面润湿性能研究

以甲基丙烯酸2-全氟辛基乙酯( FOEMA)分别和不同烷烃链长丙烯酸酯(RA,CH2=CHCOOCnH2n+1,n=4,8,12,16,18)为单体,用自由基聚合法合成了一系列的含氟丙烯酸酯共聚物,通过X射线衍射(XRD)和示差扫描量热法(DSC)对共聚物进行了表征,发现结晶性与丙烯酸酯的烷烃链长度密切相关,当n=4,...     

Poly(bis‐2,2,2‐trifluoroethoxymethyl oxetane): Multiple crystal phases,crystallization‐induced surface topological complexity and enhanced hydrophobicity

Semicrystalline poly(bis‐trifluoroethoxymethyl)oxetane, P(B‐3FOx), was prepared by cationic ring‐opening polymerization at ?5 °C with M_n up to 21 kDa. Differences in cooling rates from the melt have substantial effects on crystal phase, percent crystallinity, surface topography, and wetting behavior. DSC and WAXD show that cooling from the melt at slow rates (<5 °C/min) gives α‐P(B‐3FOx) with ΔH_f = 22–27 J/g. Quenching from the melt results in β‐P(B‐3FOx) for which a mesophase structure is suggested. β‐P(B‐3FOx) melts at 53 °C followed by recrystallization to α‐P(B‐3FOx). Solution casting from THF results in third phase, γ‐P(B‐3FOx). TM‐AFM and SEM imaging for α‐P(B‐3FOx) showed that cold crystallization at 25 °C brought about increased crystallinity and surface topologies characterized by sharp asperities and lath‐shaped crystals. Spontaneous surface roughening of α‐P(B‐3FOx) results in a discontinuous three‐phase contact line with water and an increase in water sessile drop contact angle from 106° to 136°. The ～30° increase in water contact angle was attributed primarily to a topological change from a relatively smooth surface (Wenzel state) to an asperity‐rich surface yielding a discontinuous three‐phase contact line (composite of Wenzel and Cassie‐Baxter state). The oleophobicity for this polymer, which contains only a single ? CF₃ end group on each side chain, compares favorably with more highly fluorinated acrylates. © 2010 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 48: 1022–1034, 2010     

Super-hydrophobicity and oleophobicity of silicone rubber modified by CF4 radio frequency plasma

Owing to excellent electric properties, silicone rubber (SIR) has been widely employed in outdoor insulator. For further improving its hydrophobicity and service life, the SIR samples are treated by CF₄ radio frequency (RF) capacitively coupled plasma. The hydrophobic and oleophobic properties are characterized by static contact angle method. The surface morphology of modified SIR is observed by atom force microscope (AFM). X-ray photoelectron spectroscopy (XPS) is used to test the variation of the functional groups on the SIR surface due to the treatment by CF₄ plasma. The results indicate that the static contact angle of SIR surface is improved from 100.7° to 150.2° via the CF₄ plasma modification, and the super-hydrophobic surface of modified SIR, which the corresponding static contact angle is 150.2°, appears at RF power of 200 W for a 5 min treatment time. It is found that the super-hydrophobic surface ascribes to the coaction of the increase of roughness created by the ablation action and the formation of [-SiF_x(CH₃)_2−x-O-]_n (x = 1, 2) structure produced by F atoms replacement methyl groups reaction, more importantly, the formation of [-SiF₂-O-]_n structure is the major factor for super-hydrophobic surface, and it is different from the previous studies, which proposed the fluorocarbon species such as C-F, C-F₂, C-F₃, CF-CF_n, and C-CF_n, were largely introduced to the polymer surface and responsible for the formation of low surface energy.     

氟硅结构对UV涂料疏水疏油性的影响

UV防污助剂主要包括有机氟和有机硅等，前者结构主要是全氟聚醚链段，后者结构主要是聚二甲基硅氧烷链，利用氟硅的低表面张力起到防污作用，所以主要链段结构的细微差异会导致性能的明显变化。本文选取C1607、C1603和KY1203分别代表聚二甲基硅氧烷、K型全氟聚醚链段和Z型全氟聚醚链段，并与UV涂料复配和固化，研究不同氟硅链段对UV涂料的疏水疏油性能的影响规律。结果证明，聚二甲基硅氧烷链段具有较强的迁移性，低添加量就可达到疏水效果，但仅能应用于低端的防水防油需求。全氟聚醚类UV防污助剂的疏水疏油性能要远优于有机硅，在较高添加量时K型全氟聚醚类UV防污助剂具有更强的疏水疏油性能。     

尼龙表面的超疏水及高度疏油改性

在聚合物表面引入多级粗糙结构并降低表面能可以提高其表面的疏水疏油性. 采用三种不同方法在尼龙6(聚酰胺)表面引入活性基团, 即或将尼龙6材料表面的酰胺键还原成仲胺, 或硅羟基化, 或使用低温等离子体处理得到羟基, 并通过X-射线光电子能谱(XPS)进行验证. 实验结果表明, 表面含有仲胺基团的尼龙6可静电吸附硅球; 而表面含有硅羟基及羟基的尼龙6可原位生长纳米硅层, 再经过3-氨基丙基三甲氧基硅烷(APS)处理可达到硅球吸附的目的. 经比较了不同改性方法对在尼龙6表面构建粗糙结构的影响, 我们认为等离子体处理更利于方便快捷地制备稳定均匀的粗糙结构. 当被全氟十二烷基三氯硅烷(Rf-Si)氟化修饰后, 具有粗糙结构的尼龙6表面均具有超疏水性, 但其疏油性则与表面引入的硅球尺寸密切相关, 如在500～900 nm硅球构建的粗糙表面上, 十六烷烃(3 μL)的静态接触角为140°左右, 滚动角为20°; 而在20～200 nm硅球构建的粗糙表面上, 其静态接触角和滚动角则分别为125°和40°左右. 实验结果还显示, 这类具有一定双疏性的尼龙表面也有较好的抗细菌粘附性.