氩等离子体后辉光区对聚四氟乙烯膜表面的优化改性

在理想管式反应器中, 采用Langmuir双电子探针和电子自旋共振(ESR)诊断技术分别定量测定了氩等离子体场中各活性物种的轴向分布, 并利用氩等离子体放电区及后辉光区对聚四氟乙烯(PTFE)进行了表面改性. 通过接触角测量、扫描电子显微镜和X 射线光电子能谱分析比较了改性前后常规及后辉光氩等离子体对PTFE表面结构及性能的影响. 结果表明, 氩等离子体中电子及离子浓度随轴向距离的增大迅速降低, 30 cm后接近于0, 而自由基浓度则降低缓慢, 40 cm处仍为初始浓度的96%. 氩等离子体放电功率、处理时间和气体流量强烈影响着PTFE表面润湿性的改善效果. 后辉光区因抑制电子和离子的刻蚀作用, 强化自由基反应, 使改性效果远优于常规氩等离子体. 经氩等离子体后辉光区短时间(30 s)处理后, PTFE表面化学成分发生了变化, F/C原子比从3.27降至2.30, O/C原子比从0.02增至0.09. 脱氟作用和含氧基团(如CO)的引入是有效改善PTFE表面润湿性的关键因素.     

Surface Modification of Poly(tetrafluoroethylene) Films by Plasma Pre-Activation and Plasma Polymerization of Glycidyl Methacrylate

Surface modification of poly(tetrafuoroethylene) (PTFE) film by plasma polymerzation and deposition of glycidyl methacrylate (GMA), in the presence and absence of Ar or O₂ plasma pre-activation, was carried out to enhance the adhesion with polyimides (PI) film in the presence of an epoxy adhesive. For deposition carried out at low RF power, a high epoxide concentration was preserved in the plasma-polymerized GMA (pp-GMA) layer on PTFE (pp-GMA-PTFE). However, high adhesion strength of the PI/pp-GMA-PTFE laminate was obtained only in the presence of O₂ plasma pre-activation of the PTFE substrates prior to plasma polymerization and deposition of GMA. In the absence of any plasma pre-activation or in the presence of Ar plasma pre-activation, the deposited pp-GMA layer on the PTFE surface could be readily removed by solvent extraction. The adhesion enhancement of the PI/pp-GMA-PTFE laminates in the presence of O₂ plasma pre-activation was attributed to the preservation of the epoxide functional groups in the pp-GMA layer, the curing of the GMA chains into the matrix of the epoxy adhesive, and the covalent bonding of the pp-GMA layer on the PTFE surface.     

苄基取代甜菜碱对聚四氟乙烯表面润湿性的影响

利用座滴法研究了两性离子表面活性剂苄基取代烷基羧基甜菜碱(BCB)和苄基取代烷基磺基甜菜碱(BSB)在聚四氟乙烯(PTFE)表面上的润湿性质,考察了表面活性剂浓度对接触角的影响趋势,并讨论了粘附张力、固-液界面张力和粘附功的变化规律.研究发现,在低浓度时,表面活性剂通过疏水作用吸附到PTFE表面,疏水链苄基取代支链化使其在固-液界面上的吸附明显低于气-液界面,接触角在很大的范围内保持不变.当体相浓度增加到大于临界胶束浓度(cmc)时, BCB和BSB分子在固-液界面上继续吸附,分子逐渐直立,造成PTFE-液体之间的界面张力(γ_SL)进一步降低,表面亲水性增加,接触角随浓度增加明显降低;另一方面, BSB由于具有较大的极性头,在高浓度时空间阻碍作用明显,导致其对PTFE表面润湿性改变程度小于BCB.     

Modification and Electrochemical Properties of Poly(phenylazomethine) Derivatives

Summary: Oligo(phenylazomethine)s (OPAs) and aniline-capped OPAs (OPA's) are used as model compounds of polyphenylazomethine (PPA), and their fundamental properties and their modification methods are investigated. Cyclic voltammograms of bis(diphenylmethyleneamino)benzene (OPA2′) showed irreversible redox response in the presence of trifluoroacetic acid. A selective synthesis of oligophenanthridine was achieved through the photocyclization of OPA2′ in concentrated sulfuric acid. Stepwise complexation behavior in dendritic poly(phenylazomethine)s (DPAs) was supported by the shell-selective reduction of the imines. Using the shell-selective reduction method and the terminal-modification method of the DPAs, the core and terminals of DPAs were functionalized by ferrocene units, respectively.     

Electroless Deposition of Copper on Poly(tetrafluoroethylene) Films Modified by Plasma-Induced Surface Grafting of Poly(4-vinylpyridine)

Argon plasma-pretreated poly(tetrafluoroethylene) (PTFE) films were solution coated with a thin layer of poly(4-vinyl pyridine) (P4VP). Subsequent exposure of the films to argon plasma resulted in the grafting of P4VP on the PTFE films. Electroless plating of copper could be carried out effectively on the P4VP-grafted PTFE (P4VP-g-PTFE) surface after PdCl₂ activation and in the absence of SnCl₂ sensitization (the Sn-free process). The catalytic processes of the electroless plating of copper in the presence and absence of sensitization by SnCl₂ were also compared. The effect of glow discharge conditions on the P4VP concentration and the adhesion strength of the electrolessly deposited copper was investigated. The T-peel adhesion strength of the electrolessly deposited copper with the graft-modified PTFE film was improved in the absence of SnCl₂ sensitization and could reach about 3 N/cm. PdCl₂ activation and electroless deposition of copper could not be carried out on the pristine or the Ar plasma-treated PTFE surface in the absence of prior sensitization by SnCl₂. X-ray photoelectron spectroscopic (XPS) analysis revealed that the electrolessly deposited copper delaminated from the P4VP-g-PTFE film by cohesive failure inside the PTFE film.     

支链化阳离子和甜菜碱表面活性剂对聚四氟乙烯表面润湿性的影响

利用座滴法研究了支链化阳离子表面活性剂十六烷基羟丙基氯化铵(C₁₆GPC)和两性离子表面活性剂十六烷基羧酸甜菜碱(C₁₆GPB)在聚四氟乙烯(PTFE)表面上的吸附机制和润湿性质, 考察了表面活性剂浓度对表面张力、接触角、粘附张力、固液界面张力和粘附功的影响趋势. 研究发现, 低浓度条件下, 表面活性剂疏水支链的多个亚甲基基团与PTFE表面发生相互作用, 分子以平躺的方式吸附到固体界面; 支链化表面活性剂形成胶束的阻碍较大, 浓度大于临界胶束浓度(cmc)时, C₁₆GPC和C₁₆GPB分子在固液界面上继续吸附, 与PTFE作用的亚甲基基团减少, 分子逐渐直立, 固液界面自由能(γ_sl)明显降低. 对于支链化的阳离子和甜菜碱分子, 接触角均在浓度高于cmc后大幅度降低.     

Surface Modification of Carbon Nanotube by Poly(ethylene glycol) for the Preparation of Poly(vinyl alcohol) Nanocomposite

Herein, PEGylated multi-walled carbon nanotube (MWNT) was prepared for the successive fabrication of poly(vinyl alcohol) PVA/MWNT nanocomposite film by solution casting. The surface modified MWNT showed a good colloidal stability in a polar solvent, i.e., water. Also, the PEGylated MWNT had an improved dispersion stability in aqueous PVA solution. The mixture of PEGylated MWNT and PVA dissolved in water was film casted and the dispersion uniformity and corresponding improvement of electrical conductivity were investigated. The electrical conductivity of PVA/modified MWNT composite film was three-fold higher than that of PVA/pristine MWNT composite film due to the much improved distribution uniformity of modified MWNT in PVA matrix.     

Reactive Conjugated Polymers: Synthesis,Modification, and Electrochemical Properties of Polypentafluorophenylacetylene (Co)Polymers

(Co)Polymers containing pentafluorophenylacetylene (F₅PA) have been prepared for the first time mediated by [Rh(nbd)Cl]₂/NEt₃ to give materials with properties typical of poly(phenylacetylene)s prepared with this catalyst/co‐catalyst combination. It is demonstrated that the F₅PA repeat units in these new (co)polymers serve as convenient reactive species for post‐polymerization modification with thiols via para‐fluoro aromatic nucleophilic substitution reactions to give an entirely new family of novel thioether‐functional polyene materials accompanied by absorption maxima shifts of up to 130 nm. Finally, the electrochemical properties of these new fluorinated polyene materials are briefly examined and the distinct difference in behavior of the F₅PA homopolymer versus polyphenylacetylene, copolymers, and functional derivatives is highlighted.

     

聚二甲基硅氧烷微流控芯片的紫外光照射表面处理研究

研究了紫外光化学表面改性对聚二甲基硅氧烷(PDMS)微流控芯片的片基间粘接力及毛细管通道电渗流性能的影响.PDMS片基经紫外光射照后,粘接力增强,可实现PDMS芯片的永久性封合,同时亲水性得到改善,通道中的电渗流增大.与文献报道的等离子体表面处理方法比较,采用紫外光表面处理,设备简单,操作方便,耗费少,是一种简单易行的聚二甲基硅氧烷芯片表面处理方法.     

Ultrasonic Modification of Polymers. I. Degradations of Polystyrene in the Presence of Various Poly(alkyl Methacrylates)

Ultrasonic (70 W, 20 kHz) degradations of polystyrene (PS) have been carried out with various poly(alkyl methacrylates) (PRMA) for periods of 3 h at 27°C in toluene (2.0 to 5.0% solutions). The isolation of sequence copolymers thus prepared from their associated homopolymers was achieved by employing selective solvents (solvent for one homopolymer but a precipitant for the second homopolymer in the mixture). The recovered products were analyzed by gel permeation chromatography (GPC), infrared spectroscopy (IR), and viscometry. These analyses showed that when the substituents in PRMA were methyl, ethyl, isopropyl, n-butyl, isobutyl, or phenyl, sequence copolymers with segments from PS as well as from poly(alkyl methacrylate) were obtained. However, when the substituents on PRMA were hexyl, isodecyl, lauryl, hexadecyl, octadecyl or isobornyl there were no sequence copolymers formed. The decrease in the intrinsic viscosity of the recovered homopolymers and shifts of their GPC chromatograms toward the low molecular weight end suggest that on sonification PRMA samples having bulkier substituents do degrade and yield radicals which, however, do not recombine with those from polystyrene. Furthermore, ultrasonic degradation of polystyrene is found to be dependent on the chain stiffness of the poly(alkyl methacrylates).     

聚二甲基硅氧烷基质微流控芯片通道的氧气氛改性研究

通过将新制的PDMS微流控芯片置于氧气氛中对通道表面进行处理的简单方法,使电渗流大小及稳定性有了显著的改善。同时研究了氧气处理PDMS通道表面的时间对电渗流的影响,得到氧气处理的最佳时间为3d。讨论了氧气作用于PDMS芯片表面的机理。在氧气处理3d的PDMS微流控芯片上进行氨基酸分离实验,得到较好的分离效果。     

Ultrasonic Modification of Polymers. II. Degradation of Polystyrene,Substituted Polystyrene,and Poly(n-vinyl Carbazole) in the Presence of Flexible Chain Polymers

Abstract

Ultrasonic (20 kHz, 70 W) solution degradations of polystyrene, substituted polystyrenes, and poly(n-vinyl carbazole) have been carried in toluene and tetrahydrofuran at 27 and -20°C in the presence of flexible chain polymers. Polystyrene formed block copolymers at 27°C with stiff-chain polymer PVCz; however, in the presence of flexible chain polymers, e.g., poly(vinyl methyl ketone) or poly(vinyl methyl ether), there were no block copolymers formed. Poly(n-vinyl carbazole) does not seem to form any block copolymers at 27°C with flexible chain polymers, e.g., poly(octadecyl methacrylate) and poly(ethyl methacrylate). Poly(p-chlorostyrene) and poly(p-methoxystyrene) also do not form block copolymers at 27°C with poly(octadecyl methacrylate) but do so with poly(hexadecyl methacrylate). It is quite possible that these may only be blends of two homopolymers. Poly(octa-decyl methacrylate) does yield a block copolymer when sonicated at -15°C with poly(p-isopropyl α-methylstyrene).     

聚(β-羟基丁酸酯)和β-羟基丁酸酯-β-羟基戊酸酯共聚物与可生物降解高分子共混改性研究进展

总结了近年来聚(β-羟基丁酸酯)、β-羟基丁酸酶—β-羟基戊酸酯共聚物与可生物降解高分子共混物的相容性、结晶性、热性能、加工性能、力学性能和生物降解性能。通过共混。聚(β-羟基丁酸酯)与—β-羟基丁酸酶卢羟基戊酸酯共聚物的性能得到显著改善。     

Immobilization of Glucose Oxidase on Cellulose／Cellulose Acetate Membrane and its Detection by Scanning Electrochemical Microscope （SECM）

Cellulose/cellulose acetate membranes were prepared and functionalized by introducingamino group on it, and then immobilized the glucose oxidase (Gox) on the functionalizd membrane.SECM was applied for the detection of enzyme activity immobilized on the membrane.Immobilized biomolecules on such membranes was combined with analysis apparatus and can beused in bioassays.     

Poly(Organophosphazenes): Use in the Improvement of Standard Materials. Application to the Modification of Surface Properties of Poly(Vinyl Alcohol)

Abstract

Modification of surface properties of poly(vinyl alcohol) by grafting of poly(organophosphazenes).     

Surface Modification of Gold by Quercetin Monolayer for the Electrochemical Determination of Copper(II)

A quercetin monolayer has been prepared on top of the self‐assembled 3‐mercaptopropionic acid (MPA) layer for the copper ion determination. Cu²⁺ ions are readily accumulated on this modified electrode through the complex formation and electrochemically detected. With a quercetin layer, the redox process of Cu²⁺ became more reversible than at the MPA‐modified electrode. Complexation sites in MPA and quercetin were occupied within five min when the electrode was immersed in 10 μM Cu²⁺ solution. The MPA and quercetin layers were stable enough to allow repeated EDTA treatment to remove adsorbed Cu²⁺ for the surface regeneration. Only 7% decrease was found after ten times regeneration and use. Linear current response was found over the concentration range of 1 nM and 10 μM with detection limit of 0.1 nM. Common interfering ions such as Cd²⁺, Zn²⁺, and Fe^2+/3+ did not show any electrochemical response in the potential range of Cu²⁺ determination.     

聚乙二醇和叶酸对层状双金属氢氧化物颗粒的表面修饰

以具有伪装隐形作用的聚乙二醇(PEG)和具有靶向作用的叶酸(FA)为修饰剂, 以氨丙基三甲氧基硅烷(APTMS)为连接剂, 对Mg₃Al-NO₃层状双金属氢氧化物(LDH)进行了表面修饰, 制备了LDH-PEG-FA纳米颗粒, 并通过X射线衍射(XRD)、 透射电子显微镜(TEM)、 紫外-可见光谱(UV-Vis)、 傅里叶变换红外光谱(FTIR)、 粒度分布分析和元素分析等技术对其结构进行了表征. 结果表明, PEG和FA的修饰量可由其原料配比调控, 修饰后的产物具有良好的水再分散性, 这主要源于修饰层的空间位阻效应. 预期LDH-PEG-FA同时具有伪装隐形性和靶向性, 可用于药物载体等领域.     

超支化聚胺-酯改性聚二甲基硅氧烷微流控芯片的紫外检测应用

采用超支化聚胺-酯对经过氧气氛处理的PDMS微流控芯片表面进行改性.成功地将超支化聚胺-酯涂覆到PDMS表面,使其表面的接触角由108°±1°降到32°±20°,改善了其亲水性;改性过后通道内的电渗流得到了有效抑制,远低于未改性通道内的电渗流.同时,将芯片通过专门设计的通道与毛细管连接在一起,在紫外检测波长214nm,...     

Surface Modification Strategies to Improve the Osseointegration of Poly(etheretherketone) and Its Composites

In the last 5 years, a wide variety of surface modification strategies are explored to improve the integration of poly(etheretherketone) (PEEK) implants with bone. Since PEEK does not support bone on‐growth, its surface properties need to be tailored to promote osteogenesis at the bone‐implant interface. Surface modifications applied to achieve this response range from simple surface morphology changes to the deposition of osteoconductive coatings. Of the many methods, titanium and/or hydroxyapatite coatings, extrusion to create surface pores, and an accelerated neutral atom beam treatment have been approved by the U.S. Food and Drug Administration to improve the integration of PEEK spinal cages. The success of these surface modifications brings hope for the clinical translation of other techniques in the future, but there are several limitations that may be preventing other treatments from reaching the clinic. This review describes numerous strategies that have been applied to PEEK‐based implants for improving their osseointegration and enhancing their antibacterial properties. The review concludes with a discussion about future directions for the field and provides suggestions for advancing clinical translation of surface‐modified PEEK implants to improve the lives of patients in need of these implants.     

聚醚醚酮表面的亲水改性和胶原蛋白固定化

采用紫外光接枝法对聚醚醚酮(PEEK)表面进行化学修饰和生物分子固定化.首先向PEEK表面引入亲水性的丙烯酰胺,并以此为反应位点通过戊二醛将胶原和胶原蛋白固定在PEEK表面.用接触角测定仪、扫描电镜、荧光标记和X射线光电子能谱等对改性薄膜进行了表征.结果表明,PEEK上丙烯酰胺的接枝密度高达50.9μg/cm~2;改性薄膜表面浸润性显著提高,水接触角最低降至(22±3)°.荧光标记胶原固定的PEEK薄膜荧光发射光谱强度最高,并在X射线光电子能谱中检测到N元素,表明胶原已固定化,固定胶原蛋白的浓度为10.2μg/cm~2.