棉织物表面引发聚合亲水性高分子膜的研究

以马来酸酐预接枝修饰纯棉机织物,重点探究了紫外光引发聚合甲基丙烯酸羟乙酯(HEMA)的浓度对其在修饰后棉织物表面聚合膜形貌的影响和膜形貌对织物表面结构和亲水性的影响.研究表明,马来酸酐在DMF/LiCl(5%)体系中,反应温度T=90℃、时间t=4h、浓度为1.5mol/L时,在织物表面的接枝率可达到8.87%;红外光谱分析发现,接枝后的棉织物在1 728cm-1和1 641cm-1处出现了明显的羰基峰和碳碳双键峰.通过场发射扫描电子显微镜和水接触角仪对PHEMA聚合膜在织物表面的形貌结构及亲水性进行了表征.结果表明,PHEMA聚合膜较好地覆盖了纤维之间的孔隙;织物表面的亲水性有所下降,其水接触角最高可达130°左右,但大约16s后全部渗进织物内部.     

涤纶织物表面化学镀Ni-Co-Fe-P合金的研究

采用化学镀技术在涤纶织物表面涂覆一层Ni-Co-Fe-P四元合金,用扫描电子显微镜(SEM)、X射线能谱仪(EDS)和X射线衍射仪(XRD)等方法对镀层的形貌、组分及结构进行表征.结果表明,镀层表面较平整光滑,厚度均匀;镀层中铁钴含量约24%,但铁的含量明显较钴高,属非正常沉积,磷含量仅3.2%,属低磷镀层;对镀层进行不同温度热处理会有Ni2P、FeNi3等新相生成,且温度越高生成的新相越多;镀层有一定的导电能力,且随着镀层厚度的增加其导电能力显著提高.     

Plasma nano-modification of poly(ethylene terephthalate) fabric for pigment adhesion enhancement

Poly(ethylene terephthalate) (PET) fabrics were modified by treating with radio frequency (RF) plasma of different gases, including argon (Ar), nitrogen (N2), oxygen (O2) and sulfur hexafluoride (SF6), under varied power (50-150 watt) and time period (0.5-20 min). Observations indicated that plasma has affected the morphology and roughness of PET fiber surface in the nano-scale level. After plasma treatment, test patterns were printed by inkjet printer directly onto the sample surface. The enhancement of color printing performance on PET fabric by plasma treatment was evaluated by color spectroscopy. The surface nano-modified PET fabrics by Ar, N2, O2, and SF6 plasmas all exhibited enhanced color yield. AFM, SEM, FTIR-ATR and XPS results suggested that the improved pigment color yield was neither clearly contributed by the wettability of the fabrics nor the polar group induced onto the fiber surfaces but rather mainly by the alteration of surface roughness.     

Hydrophobic–hydrophilic dichotomy of the butterfly proboscis

Mouthparts of fluid-feeding insects have unique material properties with no human-engineered analogue: the feeding devices acquire sticky and viscous liquids while remaining clean. We discovered that the external surface of the butterfly proboscis has a sharp boundary separating a hydrophilic drinking region and a hydrophobic non-drinking region. The structural arrangement of the proboscis provides the basis for the wetting dichotomy. Theoretical and experimental analyses show that fluid uptake is associated with enlargement of hydrophilic cuticular structures, the legulae, which link the two halves of the proboscis together. We also show that an elliptical proboscis produces a higher external meniscus than does a cylindrical proboscis of the same circumference. Fluid uptake is additionally facilitated in sap-feeding butterflies that have a proboscis with enlarged chemosensory structures forming a brush near the tip. This structural modification of the proboscis enables sap feeders to exploit films of liquid more efficiently. Structural changes along the proboscis, including increased legular width and presence of a brush-like tip, occur in a wide range of species, suggesting that a wetting dichotomy is widespread in the Lepidoptera.     

Study on formation process of surface plasma

A suitable equation group used to describe the establishment process and characteristics of induced dielectric barrier discharge (IDBD) plasma have been determined. Some experiments have been done which are used to examine whether the equation group is right or not. The examination results show that the equation groups are correct and can be used to design an IDBD device.     

Improvement in the hydrophilic property of inner surface of polyvinyl chloride tube by DC glow discharge plasma

A DC glow discharge plasma was generated inside polymer tube at low pressure. The polyvinyl chloride (PVC) tube with 4 mm inner diameter and 50 mm length was treated by Ar plasma generated inside the tube. The hydrophilic property of the inner surface of the PVC tube was remarkably improved after the plasma treatment. The water contact angle of the inner surface decreased to 37° from 75° for the untreated sample as the treatment time increase to 30 min. The water contact angle of plasma-treated PVC tube decreases with increasing applied voltage, but increase with increase in working pressure. When the Ar plasma-treated PVC tubes are stored in air at room temperature, the contact-angles of the inner surface quickly increases and finally reaches a plateau value which is still considerably lower than the 75° for the untreated sample.     

等离子体表面接枝改性聚对苯二甲酸乙二醇酯的血液相容性研究

利用等离子体表面接枝改性方法在聚对苯二甲酸乙二醇酯(polyethylene terephthalate，PET)材料表面接枝不同分子量的聚乙二醇(PEG)，体外血液相容性实验表明．接枝了PEG的PET材料的血液相容性与PEG的分子量有关；当接枝的PEG分子量达到6000时，材料的血液相容性最好。     

冷等离子体处理对涤纶纤维表面性能的影响

采用冷等离子体技术处理涂纶纤维,利用ESCA分析了冷等离子体处理前后的纤维表面元素组成,官能团类型的变化,通过比较处理前后浸润性,涂纶纤维／环氧复合材料的层间剪切强度,研究了冷等离子处理对涤纶纤维表面性质的影响,结果表明：绦纶纤维经冷等离子处理后表面含氧的极性基团增加,纤维表面的浸润性显著改善,涤纶纤维／环氧复合材料界面性能增强。     

低温CF4等离子体改性亲水聚醚砜膜及其在直接接触式膜蒸馏中的应用

膜蒸馏是一种低能耗、高效率的海水淡化技术.文章借鉴了制备压力推动膜材料的思路,采用非对称、孔结构高度连通的亲水聚醚砜膜,通过CF4等离子体表面改性,将亲水膜改性为疏水膜材料,并应用于直接接触式膜蒸馏(DCMD)过程.对膜的结构,接触角和DCMD性能进行了表征.结果显示,改性后PES膜表面水接触角达120°.以4％ NaC1水溶液为原料,膜蒸馏中水通量达44 kg/(m2·h)(盐水温度72.6℃,冷水侧温度15℃),对盐的截留率达99.96％.实验表明,孔连通性较好的小孔径聚醚砜膜具有较好的膜蒸馏性能,可能成为具有商业用途的膜材料.     

Superhydrophobic surface directly created by electrospinning based on hydrophilic material

We describe a method to form hydrophobic surfaces using PHBV (Poly (hydroxybutyrate-co-hydroxyvalerate))—a kind of intrinsically hydrophilic material. The concentration of polymer solutions was varied to control the surface morphology and resultant wetting property. The as-prepared films were characterized by micro-scale valley-and-hill structure, which was formed by aggregating of electrospun beads. The bead morphology changed from smooth to porous and popcorn-like with decreased concentrations. The shape of water droplet on these surfaces had contact angles ranging from 110.7 to 158.1°, with a maximum standard deviation of 2.5°. It was found that both the micro and nanostructure were important to create a superhydrophobic surface.     

低温等离子体液相接枝处理电纺PET膜的制备与研究

采用氮气(N2)低温等离子体引发苯二甲酸乙二醇酯(PET)纳米纤维薄膜表面接枝,液相低温等离子体处理接枝丙烯酸单体,通过电镜照片、水接触角测试、FTIR测试及力学测试,讨论了液相接枝处理后,薄膜的形态及性能的变化。实验中接枝处理的工艺条件是,丙烯酸接枝溶液体积浓度10%,接枝温度60℃,接枝时间2h。液相低温等离子体接枝处理后,薄膜的表面亲水性得到了有效的提高。     

Characterization of surface modified polyester fabric

Woven polyethylene terephthalate (PET) fabric has been used in the construction of vascular grafts and sewing ring of prosthetic heart valves. In an effort to improve haemocompatibility and tissue response to PET fabric, a fluoropolymer, polyvinylidine fluoride (PVDF), was coated on PET fabric by dip coating technique. The coating was found to be uniform and no significant changes occurred on physical properties such as water permeability and burst strength. Cell culture cytotoxicity studies showed that coated PET was non-cytotoxic to L929 fibroblast cell lines. In vitro studies revealed that coating improved haemocompatibility of PET fabric material. Coating reduced platelet consumption of PET fabric by 50%. Upon surface modification leukocyte consumption of PET was reduced by 24%. About 60% reduction in partial thromboplastin time (PTT) observed when PET was coated with PVDF. Results of endothelial cell proliferation studies showed that surface coating did not have any substantial impact on cell proliferation. Overall results indicate that coating has potential to improve haemocompatibility of PET fabric without affecting its mechanical performance.     

Characterization of surface modified polyester fabric

Woven polyethylene terephthalate (PET) fabric has been used in the construction of vascular grafts and sewing ring of prosthetic heart valves. In an effort to improve haemocompatibility and tissue response to PET fabric, a fluoropolymer, polyvinylidine fluoride (PVDF), was coated on PET fabric by dip coating technique. The coating was found to be uniform and no significant changes occurred on physical properties such as water permeability and burst strength. Cell culture cytotoxicity studies showed that coated PET was non-cytotoxic to L929 fibroblast cell lines. In vitro studies revealed that coating improved haemocompatibility of PET fabric material. Coating reduced platelet consumption of PET fabric by 50%. Upon surface modification leukocyte consumption of PET was reduced by 24%. About 60% reduction in partial thromboplastin time (PTT) observed when PET was coated with PVDF. Results of endothelial cell proliferation studies showed that surface coating did not have any substantial impact on cell proliferation. Overall results indicate that coating has potential to improve haemocompatibility of PET fabric without affecting its mechanical performance.     

Characterization of the tool/fabric and fabric/fabric friction for woven-fabric composites during the thermostamping process

The dynamic coefficients of friction for Twintex® commingled glass-polypropylene balanced plain-weave and unbalanced twill-weave fabrics at the tool/fabric and fabric/fabric interfaces during the composite thermostamping process are characterized. The effects of fabric velocity and pressure on the coefficients of friction under conditions similar to those during the thermostamping process are studied. A phenomenological friction model accounting for pressure and velocity dependence is developed based on the experimental results and implemented into the commercial finite element codes ABAQUS/Explicit and LS-DYNA via user-defined subroutines. The mechanical behavior of the fabric is modeled using a mesoscopic approach. The friction subroutines are validated with a finite element model of the experimental friction test. The forming of a hemispherical dome is simulated using ABAQUS and LS-DYNA. Punch forces and yarn stresses are compared between variable friction and constant friction models, and the simulation results justify the necessity for a variable friction model to accurately predict part quality.     

Effects of additives on the photo-induced grafting polymerization of N-isopropylacrylamide gel onto PET film and PP nonwoven fabric surface

In this study, the thermosensitive gels were grafted onto plasma-activated polyethylene terephthalate (PET) film and polypropylene (PP) nonwoven fabric surface. The Ar* plasma pretreatment was carried out and subsequent photo-induced surface graft polymerization was employed to graft the N-isopropylacrylamide (NIPAAm). The effects of additives during the grafting were accessed. The additives used were ammonium peroxodisulfate (APS, initiator), N,N,N′,N′-tetra-methylethylene-diamine (TEMED, promoter) and N,N′-methylenebisacrylamide (NMBA, cross-linking agent). The results indicate that the additives of APS, TEMED and NMBA will be beneficial in promoting the grafting. The additives, including all three, will give the best result. These grafted gels exhibit a lower critical solution temperature (LCST) at about 32 °C, which shows that the temperature-responsive behavior of bulk P (NIPAAm) hydrogel was preserved.     

Aerosol assisted deposition of melamine-formaldehyde resin: Hydrophobic thin films from a hydrophilic material

An intrinsically hydrophilic melamine-formaldehyde thin film (water contact angle of 34° for a cast flat surface) was deposited on a glass substrate using aerosol assisted chemical vapour deposition. The resultant resin films showed a highly developed microstructure consisting of spherical structures that were agglomerated into towers. The surface wetted via a Cassie-Baxter mechanism with air trapped underneath the water droplets and resultant water contact angles as high as 135°. Film thickness and coverage were crucial in determining the wetting properties. Films with limited deposition gave hydrophilic results, whereas thicker films greater than 4 μm were superhydrophilic. This behaviour could be explained by the ease of trapping air under the coating. It is shown that the water wetting properties of a single material can be altered from superhydrophilic to near superhydrophobic by controlling the surface microstructure in a single-step aerosol route.     

Surface properties and in vitro analyses of immobilized chitosan onto polypropylene non-woven fabric surface using antenna-coupling microwave plasma

Antenna coupling microwave plasma enables a highly efficient and oxidative treatment of the outermost surface of polypropylene (PP) non-woven fabric within a short time period. Subsequently, grafting copolymerization with acrylic acid (AAc) makes the plasma-treated fabric durably hydrophilic and excellent in water absorbency. With high grafting density and strong water affinity, the pAAc-grafted fabric greatly becomes feasible as an intensive absorbent and as a support to promote chitosan-immobilization through amide bonds. Experimental result demonstrated that surface analyses by FTIR-ATR have shown that R–CONH–R', amide binding were emerged between pAAc and chitosan. The XPS measurements on C_1s 286.0 eV (C–OH), 286.5 eV (C–N) and 288.1 eV (O=C–NH) also could be found. Bioactivity assessments on the chitosan-immobilized surfaces were anticipated by activated partial thromboplastin time (aPTT), thrombin time (TT), and fibrinogen concentration. By means of cell counter we counted the ratio of blood cell adhesion on the modified fabric matrix. After human plasma incubated with the chitosan-immobilized PP fabrics, the required time for aPTT and blood cell adhesion increased significantly, while fibrinogen concentration and TT did not change. Due to the capability of anticoagulation and cell adhesion, the chitosan-immobilized PP fabric can be used as the substrate for cell culturing and then developed the wound-dressing substitute for second-degree burn.     

Heterogeneous nucleation and growth mechanism on hydrophilic and hydrophobic surface

Heterogeneous nucleation and nucleation period of calcium carbonate on the mica and the highly oriented pyrolytic graphite (HOPG) substrate have been investigated. Calcium carbonate was prepared by the reaction of calcium nitrate solution with sodium carbonate solution. In the reaction crystallization of calcium carbonate, calcite and vaterite were nucleated on the both substrates. We counted the number of crystalline calcium carbonate on the substrates obtained from various initial supersaturations of calcium carbonate. The number of crystals on the mica surface was much higher than on the HOPG surface. Additionally, the number of crystals on the mica was greatly affected by changing of initial supersaturation. In order to explain the difference between the mica and the HOPG surface, a possible model for the nucleation period of calcium carbonate has been discussed. The surface crystallization on the mica and the HOPG could be described by considering the supersaturation in the bulk solution and in the vicinity of substrate, separately.     

Development of biomaterial using durable surface wettability fabricated by plasma-assisted immobilization of hydrophilic polymer

As a series of plasma-assisted immobilization of bio-molecule for bio application, 12-mer oligo-DNA was immobilized on the surface of LDPE-VEMAC sheet, which was prepared by plasma-assisted method and possessed a lot of carboxyl groups on the surface. A larger amount of oligo-DNA could be immobilized by the present technique compared with other methods reported. The sheet immobilizing oligo-DNA detected the complementary oligo-DNA and was reusable for several times at least under present experimental condition. This method would be useful for the fabrication of the analytical instrument such as DNA chip, protein chip and affinity chromatography.