疏水二氧化硅/聚苯乙烯超疏水复合涂层的简易制备及其防沾污性研究

采用喷枪及家用简易喷雾器在含有聚乙烯(PE)膜的纸张表面制备了含疏水二氧化硅纳米颗粒和聚苯乙烯的超疏水复合涂层。随着疏水二氧化硅纳米颗粒含量的增加,表面逐渐被二氧化硅颗粒覆盖,并且形成微纳米孔洞结构,达到超疏水性,并具有良好的耐粘附稳定性,水、牛奶和橙汁等液滴可从这些超疏水表面滚落而不残留,具有良好的防沾污能力。     

透明超疏水玻璃表面的制备及性能研究

目的研究透明超疏水玻璃的制备及性能。方法以纳米二氧化硅和无水乙醇为原料制成半透明乳液,然后将乳液喷涂在玻璃表面,再通过接触角测试、透光率测试仪等手段对玻璃表面的性能进行研究。结果在玻璃基材表面构建了与水滴接触角高达158°±2°,滚动角低至1°的透明超疏水表面。当喷涂液中纳米二氧化硅的质量分数为1.5%时,获得的超疏水玻璃表面具有优异的防水性、抗污易清洁性和透明性。结论在玻璃基底上制备透明超疏水表面可以大大提高玻璃表面的防水、防污性,并使玻璃表面更易于清洁,有利于减少玻璃包装材料清洗时的用水量和洗涤剂用量,从而增强玻璃包装材料的生态环保效应。     

纳米SiO2对聚氨酯清漆性能的影响

通过表面改性技术获得疏水性的纳米二氧化硅粒子,粒径约50nm.在机械搅拌和超声场的共同作用下,将纳米二氧化硅分散到聚氨酯清漆中,制得纳米二氧化硅复合涂料.失重法腐蚀实验、阳极极化曲线和交流阻抗测试结果表明,加入纳米二氧化硅后,聚氨酯清漆的耐蚀性能提高.同时改性后的聚氨酯清漆漆膜的附着力增加,抗老化性能提高.     

透明超疏水聚乙烯薄膜的制备及性能分析

目的研究包装透明超疏水聚乙烯(PE)薄膜的制备方法及其性能。方法以纳米二氧化硅和无水乙醇为原料,将纳米二氧化硅溶于无水乙醇制得二氧化硅半透明溶液,采用浸渍提拉法将PE膜在二氧化硅溶液中浸泡数分钟后提拉取出并自然干燥,然后用扫描电子显微镜、接触角测量仪、透光率雾度测定仪测量膜表面的性能,并进行研究分析,用污水浸泡样品数天后测量其抗污性。结果成功制备了透明超疏水PE薄膜,其表面与水的接触角高达(171±2)°,滚动角低至1°。当纳米二氧化硅的质量浓度为10 mg/mL时,其薄膜表面表现出了优异的透明性、防水性和抗污染自清洁性。结论采用简易方法制备了透明超疏水聚乙烯塑料薄膜,提高了聚乙烯膜超疏水自清洁的性能,大大增强了聚乙烯膜在包装领域的应用前景。     

A3碳钢表面PDMS-SiO_2/PANI超疏水膜的制备及其防腐蚀性能

为了提高超疏水膜的使用寿命,通过改变聚二甲基硅氧烷修饰的二氧化硅(PDMS-SiO_2)纳米粒子的含量,用简单的提拉法在A3碳钢表面构建一层包含聚苯胺(PANI)、PDMS-SiO_2和环氧树脂的超疏水膜。通过扫描电镜(SEM)、红外光谱仪和接触角测量仪对其表面进行表征。PDMS-SiO_2纳米粒子不仅能够增加膜的表面粗糙度,而且能够降低膜的表面能,当PDMS-SiO_2含量达到25.0%时,所制备的膜具有超疏水性。采用电化学工作站对复合膜的防腐蚀性能进行研究,结果表明:与传统的聚苯胺环氧树脂涂层相比,采用PDMS-SiO_2/PANI构建的超疏水膜具有更好的防腐蚀效果。     

PVDF/SiO2/PDMS涂层超疏水纺织品性能

目的 针对普通纺织品材料防水性和防污性较差的问题,制备具有自清洁功能的超疏水涂层纺织品,并研究其性能.方法 以涤纶织物为基材,通过非溶剂诱导相分离法,使用聚偏氟乙烯和疏水纳米二氧化硅复合液在纺织品表面构筑微纳粗糙结构,采用聚二甲基硅氧烷对其进行疏水化处理,获得自清洁超疏水涂层纺织品.采用扫描电子显微镜、X射线能量散射光谱和视频光学接触角测量仪等对其结构和性能进行表征,并通过机械摩擦、洗涤、酸/碱/盐溶液浸渍和紫外光照等方法对其表面超疏水稳定性进行考察.结果 当聚偏氟乙烯质量分数为2％,疏水纳米二氧化硅质量分数为0.4％,聚二甲基硅氧烷质量分数为1％时,制备的纺织品的表面接触角可达(162.2°±0.8°),滚动角达(2.0°±0.4°),具有优异的超疏水自清洁效应;经72 h酸/碱/盐溶液浸渍、196 h紫外光照、2500次摩擦和120次家庭水洗后,其表面接触角仍大于150°,表现出优异的超疏水稳定性.结论 采用简便的非溶剂相分离法制备的涂层纺织品具有优异的自清洁性能,并且其超疏水性能具有机械耐久性和化学稳定性,有望应用于纺织材料包装领域.     

SiO_2/PDMS复合膜的制备及其渗透汽化性能研究

以PVDF为支撑层,制备了疏水性二氧化硅(SiO2)填充聚二甲基硅氧烷(SiO2/PDMS)复合膜,通过扫描电镜、接触角测试和热失重分析对复合膜微观形貌、表面疏水性和热性能进行了表征。研究发现,SiO2的加入,可以有效提高PDMS膜的表面疏水性和热稳定性。疏水性SiO2与PDMS基体结合紧密,当SiO2填充低于3%(wt,质量分数,下同)时,纳米粒子在PDMS基体中分散均匀,未发现明显团聚。将复合膜用于渗透汽化乙醇/水体系的分离,发现SiO2的加入,在填充量为1.5%时,SiO2/PDMS复合膜综合分离性能优于纯PDMS膜,尤其是操作温度升高时,与纯PDMS膜相比,复合膜分离因子下降幅度较小,而渗透通量增加较快,表现出较好的综合分离性能。     

荧光介孔二氧化硅纳米粒子的制备及其性能探究

利用单层十六烷基三甲基溴化铵(CTAB)表面活性剂包覆染料并将其转相到水中,通过溶胶-凝胶法制备以荧光染料为核、介孔二氧化硅纳米粒子(MSNs)为壳的荧光介孔二氧化硅纳米粒子。利用DLS探讨了正硅酸乙酯、表面活性剂、氨水、染料浓度对粒子粒径的影响,利用SEM、TEM、TG、UV、PL光谱分析手段对复合纳米粒子结构、形貌、热稳定性、光谱进行了表征和探讨。结果表明,随着正硅酸乙酯和氨水用量增多,粒子粒径增加;表面活性剂用量较少时粒径会较大;染料浓度较低时对粒径影响较小;制备出的粉体可以在100nm左右可控;荧光强度提高、染料与二氧化硅最佳掺杂质量比为1.5×10-3;由于是物理包覆所以热稳定性提高有限,但抗紫外耐老化性有显著的提高。     

TiO_2纳米粒子及纳米棒在活性碳纤维上的生长研究

通过两步水热方法,在活性碳纤维上依次沉积了锐钛矿型TiO_2纳米粒子及金红石型TiO_2纳米棒,SEM及XRD实验结果表明:在纤维表面预沉积锐钛矿型TiO_2纳米粒子有助于后续金红石型TiO_2纳米棒的生长。随着纳米棒的生长,纳米粒子的质量分数下降。与单纯锐钛矿型TiO_2纳米粒子负载的纤维相比,纳米棒生长时间2.5h相应的混晶TiO_2负载的活性碳纤维显示了对亚甲基蓝较高的光催化活性。在对混晶TiO_2负载的纤维用辛基三甲氧基硅烷处理后,纤维毡的表面显示超疏水性,并且水接触角随纳米棒生长时间的延长而增大。     

疏水性气相SiO2改性环氧树脂的耐电晕性能

采用砂磨机将疏水性气相SiO₂纳米粒子分散到无溶剂环氧树脂（Epoxy,EP）中,经加热固化后制备了不同掺杂量的疏水性气相SiO₂/EP复合材料,通过XRD检测和SEM表征,证实疏水性气相SiO₂纳米粒子以无定形态均匀分散在EP中。疏水性气相SiO₂/EP复合材料的理化性能测试结果表明:其热稳定性、介电常数、介电损耗和电导率均随纳米SiO₂粒子掺杂量的增加而有所升高;纳米SiO₂粒子掺杂量为2wt%时,击穿场强达到最大值为24.66 kV/mm,较纯EP材料提高了21.35%;疏水性气相SiO₂/EP复合材料耐电晕寿命随纳米SiO₂粒子掺杂量增加而增加。在室温、80 kV/mm电场强度下,纳米SiO₂粒子掺杂量为8wt%时,疏水性气相SiO₂/EP耐电晕寿命可达42.7 h,是纯EP的18.9倍。      

纳米微结构涂层的制备及其超疏水性研究

通过简便的纳米粒子填充法制备超疏水表面,将SiO2纳米粒子与含氟丙烯酸酯聚合物按不同比例混溶制备出具有不同微结构的表面,并探讨了表面微结构对润湿性能的影响.接触角测试表明,随着SiO2纳米粒子含量的增加,涂层与水接触角逐渐增大,并且当SiO2与聚合物质量比＞1.2时发生突跃,显示出超疏水性质.采用X射线光电子能谱分析了涂层表面化学环境,通过扫描电子显微镜、原子力显微镜、孔结构分析等方法观察和分析了不同SiO2纳米粒子含量时涂层表面微结构.研究结果表明,涂层表面润湿特性的变化主要归因于其表面微结构的不同.并通过粗糙表面润湿理论的Wenzel模型和Cassie模型解释了表面微结构对润湿性的影响及接触角的突跃现象.     

Influence of hydrophobic characteristic of organo-modified precursor on wettability of silica film

The objective of this study is to design new hybrid silica materials as templates with hydrophobic properties, prepared at room temperature by a base catalyzed sol–gel process. As silica sources, organoalkoxysilanes functionalized with short hydrophobic chains were used: tetraethylorthosilicate (TEOS), methyltriethoxysilane (MTES), vinyltriethoxysilane (VTES), octyltriethoxysilane (OTES) and isobutyltriethoxysilane (iTES). It was shown that hydrophobicity of the functionalized silica nanoparticles increased as a function of length of the aliphatic chains (MTES < iTES < OTES) or when, instead of a hydrophobic alkyl chains (substituting group of silica precursors), a monounsaturated group was used (VTES). It was observed that the samples responded in a specific way to each type (hydrophilic or hydrophobic) of the dropped liquid. Even though the experiments were limited to short hydrocarbon chains, they showed that there is a threshold to reach high hydrophobicity of the hybrid surface.     

介孔SiO2孔道结构对聚酰胺反渗透复合膜性能的影响

在界面聚合过程中,通过添加改进水热方法制备的球形介孔SiO2纳米材料,制备了改性的聚酰胺反渗透复合膜。使用扫描电镜、X射线衍射和氮气吸附-脱附等手段对制备的介孔SiO2纳米材料进行表征;采用反渗透膜评价装置、原子力显微镜、扫描电镜(SEM)和静态接触角仪器等手段对复合膜的性能和结构进行测试和表征;并对比了相同粒径大小的实心SiO2和介孔SiO2对膜渗透性能的影响。结果证明:成功合成了一种具有孔径分布均匀、粒径均一、比表面积较大、分散性较好的介孔SiO2纳米球形颗粒;SEM表征结果证实纳米材料在膜表面分布均匀,膜表面亲水性能提高,粗糙度变大;膜性能测试结果证实了介孔SiO2的添加使得膜在维持较高截留率的前提下,具有更高的水通量;同时,通过对比相同尺寸的实心SiO2作为添加材料,证实了介孔SiO2的孔道结构更有利于水分子的传输。当介孔SiO2添加质量为0.06%时,水通量由23L/(m2·h)提高至39L/(m2·h),对氯化钠的截留仍然维持在98%以上。     

Dispersion of amorphous silica nanoparticles via beads milling process and their particle size analysis,hydrophobicity and anti-bacterial activity

In this present work, amorphous silica is synthesized by simple solution method using sodium silicate (Na₂SiO₃) as raw material. The synthesized silica is dispersed in various dispersing agent obtained from local paint industry and used for painting application. XRD analysis revealed the existence of amorphous silica with a peak at 2θ value of 23° and the SEM analysis exemplified silica nanoparticles demonstrating spherical morphology with agglomeration. Different dispersing agents (as indicated by the codes given by paint industry) were used for the dispersion of SiO₂ by beads milling process and its effects were studied. Among the several dispersing agents used amorphous silica dispersed in SND 504 (Sodium salt of polymeric carboxylic acid with water) dispersing agent exhibit better dispersion compared to the other dispersing agents. Further, 10 wt% of SND 504 dispersing agent was optimized with the particle size to 384 nm and zeta potential value of −24.69 mV. The contact angle measurement of the dispersed silica reveals the superior hydrophobic behaviour of SiO_2, especially with 10 wt% SND 504 dispersing agent. The critical surface tension of SiO₂ with 10 wt% SND 504 dispersing agent reveal low value compared to other concentration of dispersant. Thus, the dispersed silica nanoparticles with enhanced hydrophobicity can be effectively used for painting applications as fillers. Silica dispersed in 10 wt% SND 504 dispersing agent show superior anti-bacterial activity compared to the bare silica which is also reported.     

Synthesis of monodisperse fluorinated silica nanoparticles and their superhydrophobic thin films

Monodispersive silica nanoparticles have been synthesized via the Sto?ber process and further functionalized by adding fluorinated groups using fluoroalkylsilane in an ethanolic solution. In this process, six different sizes of fluorinated silica nanoparticles of varying diameter from 40 to 300 nm are prepared and used to deposit thin films on aluminum alloy surfaces using spin coating processes. The functionalization of silica nanoparticles by fluorinated group has been confirmed by the presence C-F bonds along with Si-O-Si bonds in the thin films as analyzed by Fourier transform infrared spectroscopy (FTIR). The surface roughnesses as well as the water contact angles of the fluorinated silica nanoparticle containing thin films are found to be increased with the increase of the diameter of the synthesized fluorinated silica nanoparticles. The thin films prepared using the fluorinated silica nanoparticles having a critical size of 119 ± 12 nm provide a surface roughness of ～0.697 μm rendering the surfaces superhydrophobic with a water contact angle of 151 ± 4°. The roughness as well as the water contact angle increases on the superhydrophobic thin films with further increase in the size of the fluorinated silica nanoparticles in the films.     

Development of organic dye-doped silica nanoparticles for bioanalysis and biosensors

The combination of two silica precursors, tetraethylorthosilicate and phenyltriethoxysilane, were utilized to synthesize organic dye-doped silica nanoparticles. The hydrophobic nature of phenyltriethoxysilane keeps the organic dye in the silica matrix, whereas the hydrophilic tetraethylorthosilicate-formed silica allows the resulting nanoparticles to be dispersed in aqueous solutions. Characterization of the nanoparticles showed that they could be synthesized in the nanometer range with high photostability and minimal dye leakage. The silica matrix of the nanoparticles allows different routes of surface biomolecular modification for biosensor and bioanalysis applications. We have shown different applications of the nanoparticles in bioanalysis and in biosensing. Biotin interaction of avidin-coated nanoparticles can be used for the determination of biotinylated bovine serum albumin, and the immobilization of glutamate dehydrogenase on the nanoparticle surfaces enables the nanoparticles to be used as biosensors for glutamate determination.     

Optimization of Amorphous Silica Nanoparticles Synthesis from Rice Straw Ash Using Design of Experiments Technique

In this study, a chemical method of dissolution-precipitation was applied to produce amorphous silica nanoparticles from rice straw ash (RSA; the waste material of rice cultivation. The morphology, particle size, structure, and area of specific surface of synthesized amorphous silica nanoparticles were evaluated using transmission electron microscopy (TEM), x-ray diffraction analysis (XRD), and BET method to measure the specific surface area of materials. In addition, chemical composition of RSA used and the synthesized silica nanoparticles was studied by x-ray fluorescence (XRF) spectroscopy. The atomic concentration of synthesized silica was determined by x-ray photoelectron spectroscopy (XPS). The effects of sodium hydroxide concentration, precipitation reaction temperature, and precipitation reaction duration on the area of specific surface were determined through design of experiments (DOE) technique. Results depicted that silica nanoparticles with particle size of 10–15 nm were successfully synthesized. Average area of specific surface and purity were 327 m2/gr and 99.5%, respectively. The interactive influence of temperature and duration had the highest effect on the average area of specific surface.     

Patterned immobilisation of silicon dioxide nanoparticles on the surface of a photosensitive polymer

A photosensitive co-polymer of styrene and 4-vinylbenzyl thiocyanate was synthesised and employed for the immobilisation of aminofunctionalised silica nanoparticles (SiO₂-NP) at the polymer surface. Upon UV irradiation of the co-polymer, isothiocyanate groups are generated by a photo-isomerisation reaction of the thiocyanate groups. The silica nanoparticles were selectively immobilised in irradiated areas by immersing the illuminated polymer surface in a solution of SiO₂-NP. Depending on the time of immersion and the nanoparticle concentration, different amounts of silica can be deposited in the irradiated areas, whilst no immobilisation of SiO₂-NP is observed in the non-irradiated areas. By using photolithographic methods, patterned silica structures (μm scale) were produced on the polymer surface. The SiO₂-NP covered surfaces are of potential interest to generate protective surface layers and to carry out further functionalisation reactions of the immobilised SiO₂-NP particles.     

Silica-shelled single quantum dot micelles as imaging probes with dual or multimodality

The present study describes a stabilization of single quantum dot (QD) micelles by a "hydrophobic" silica precursor and an extension of a silica layer to form a silica shell around the micelle using "amphiphilic" and "hydrophilic" silica precursors. The obtained product consists of approximately 92% single nanocrystals (CdSe, CdSe/ZnS, or CdSe/ZnSe/ZnS QDs) into the silica micelles, coated with a silica shell. The thickness of the silica shell varies, starting from 3-4 nm. Increasing the shell thickness increases the photoluminescence characteristics of QDs in an aqueous solution. The silica-shelled single CdSe/ZnS QD micelles possess a comparatively high quantum yield in an aqueous solution, a controlled small size, sharp photoluminescence spectra (fwhm approximately 30 nm), an absence of aggregation, and a high transparency. The surface of the nanoparticles is amino-functionalized and ready for conjugation. A comparatively good biocompatibility is demonstrated. The nanoparticles show ability for intracellular delivery and are noncytotoxic during long-term incubation with viable cells in the absence of light exposure, which makes them appropriate for cell tracing and drug delivery. The presence of the hydrophobic layer between the QD and silica-shell ensures an incorporation of other hydrophobic molecules with interesting properties (e.g., hydrophobic paramagnetic substances, hydrophobic photosensitizers, membrane stabilizers, lipid-soluble antioxidants or prooxidants, other hydrophobic organic dyes, etc.) in the close proximity of the nanocrystal. Thus, it is possible to combine the characteristics of hybrid materials with the priority of small size. The silica-shelled single QD micelles are considered as a basis for fabrication of novel hybrid nanomaterials for industrial and life science applications, for example, nanobioprobes with dual modality for simultaneous application in different imaging techniques (e.g., fluorescent imaging and functional magnetic resonance imaging).     

Thermal interaction between limestone and silica

A thermodynamic analysis of the interaction between limestone and silica is carried out under normal pressure with the use of the TERRA program system. An equilibrium system is considered. The thermodynamic parameters are calculated with a step-by-step increase in temperature. The temperature of calcium silicate synthesis with respect to the initial mixture composition is found. At all possible ratios between limestone and silica, the products of the chemical reaction are determined. The reaction heat, synthesis temperature, enthalpy increment, and heat content are determined. It is shown that wollastonite isothermal synthesis proceeds at 550 K at a constant heat content, and rankinite isothermal synthesis proceeds at 750 K at a constant heat content as well. The reaction heat increases with rising limestone content until rankinite starts to form and then decreases to zero. The interaction between limestone and silica produces carbon dioxide gas, whose content grows simultaneously with the rising reaction heat. When the rankinite yield is maximal, the amount of carbon dioxide diminishes to zero, because free limestone forms and CO₂ is buried. On the basis of the results, the conclusion is drawn that the reaction proceeds with a latent exotherm due to latent limestone dissociation and formation of lime during the thermal interaction between limestone and silica.