Synthesis of new superhydrophobic nanosilica and investigation of their performance in reinforcement of polysiloxane

We reported a new facile method to synthesize superhydrophobic nanosilica using glycidoxypropyltrimethoxysilane and dodecylamine as treatment agents. Also, we systemically investigate their performance in reinforcement of poly(dimethylsiloxane) (PDMS) rubber. Fourier transform infrared spectrum, contact angle (CA) and thermogravimetric analysis (TGA) measurements were used to characterize the modified nanosilica. Results show that the inherent hydrophilicity of parent nanosilica surface can be greatly altered through this modification method. The CA of as‐prepared superhydrophobic nanosilica can reach 160.2°. The properties of as‐prepared modified nanosilica‐filled PDMS composites were systemically investigated by dynamic rheological test, scanning electron microscopy, TGA, dynamic mechanical analysis. These as‐prepared superhydrophobic nanosilica exhibit uniform dispersion in the PDMS matrix, and their composites also show good mechanical properties and distinct advantage on thermal stability compared with those of the pure silica‐filled PDMS composites. Also described is the probable mechanism for the reinforcement of as‐prepared superhydrophobic nanosilica‐filled PDMS. POLYM. COMPOS., 31:1628–1636, 2010. © 2009 Society of Plastics Engineers     

光热超疏水材料的制备与防、除冰性能研究

户外设备表面结冰给人类生活和生产带来了众多不便,研究具有防结冰性能和除冰性能的新一代防、除冰材料对于户外设备的持久稳定运行具有重要意义。本文利用模板法将三氧化二钛（Ti₂O₃）粉末和聚二甲基硅氧烷（PDMS）混合制备具有规则阵列结构的光热超疏水材料,并研究其防结冰性能与光热除冰性能。得益于Ti₂O₃优异的光热性能,制备的材料在100 mW/cm²光照条件下的光热温升可达55℃,冻结在表面的液滴可在200 s内融化,具有优异的光热转换与光热除冰性能。而PDMS材料固化后本征疏水,加规则阵列微结构后赋予材料优异的超疏水性能,其接触角高达153°,滚动角小于5°。无光照时的结冰延迟时间长达1300 s,是无光热材料表面结冰延迟时间的3倍。而在光照时由于其优异的光热性能,液滴在长达6 h的结冰测试中尚未结冰,表明材料具有优异的光热防结冰性能。研究结果论证了利用自然界丰富太阳能进行除冰的可能性,为户外设备表面除冰技术提供新的方式。     

Preparation of superhydrophobic conductive micro/nano-graphite/PDMS films on paper by simple spraying method

Paper-based materials are widely used in various fields due to their advantages, such as environmental friendliness and sustainability. However, the highly hydrophilic nature of the cellulose that makes up paper-based materials limits their use. In this paper, micron/nano-graphite/polydimethylsiloxane (PDMS) coatings with excellent superhydrophobic and conductive properties were prepared on the surface of filter paper by a simple spraying method. A mixture of micro-graphite and nano-graphite was used to form a multistage rough structure on the surface of the filter paper by spraying, and the low surface energy PDMS enhanced the adhesion of the micro-graphite and nano-graphite on the surface of the filter paper. The results showed that the samples possessed the best superhydrophobic properties when the ratio of micro-graphite to nano-graphite was 1:1, at which time the contact and rolling angles of the samples were 165.4° and 3.2°, respectively. The prepared superhydrophobic samples have good bounce and self-cleaning properties, while the samples have good mechanical stability and chemical resistance. Additionally, due to the conductivity of micro–nano-graphite, both particle sizes closely contact the sample surface, creating a conductive network. With a 1:1 ratio of micro- and nano-graphite, the coating exhibits minimal resistance at 1.89 KΩ, and the sample maintains stable conductivity even underwater. The above properties greatly extend the application range of paper-based superhydrophobic materials.     

Preparation and characterization of superhydrophobic surface based on polydimethylsiloxane (PDMS)

Biomimetic superhydrophobic surfaces exhibit excellent self-cleaning properties due to their special micro/nano-scale binary structures. In order to prepare the superhydrophobic surface of the polydimethylsiloxane (PDMS), a facile fabrication method for replicating micro/nano-scale binary aluminium structures into PDMS is presented. The microscopic morphology, composition, surface roughness (Ra) and wettability of the sample surface were characterized by scanning electron microscopy (SEM), energy dispersive spectroscopy (EDS), Fourier transform infrared (FTIR) spectroscopy, roughness measurement equipment and contact angle meter respectively. Based on the measurements of the contact angles of deionized water (DI water) and ethanediol, surface free energies of the coatings were estimated according to the Owens two-liquid method. The superhydrophobic PDMS exhibited lower surface free energy than flat PDMS with a DI water contact angle (WCA) of 165°. The surface roughness (Ra) increased with the increasing of etching time in the range 0–80?min, and then decreased with the change of etching time, similar to the variation of contact angle with etching time. Moreover, the prepared surface had different micro-morphologies and its wettability was changed by regulating the chemical etching time. In addition, the superhydrophobic PDMS also showed good self-cleaning properties and the bouncing effect of the water droplets.     

PVDF中空纤维换热管超疏水表面强化蒸气滴状冷凝传热

为了提高塑料换热管的传热性能，通过两步涂覆法制备了具有超疏水表面的复合塑料换热管。首先采用多孔PVDF中空纤维膜为支撑层，以导热材料纳米ZnO填充聚二甲基硅氧烷（PDMS）为皮层，制备了具有致密外表皮层的复合塑料换热管。其次为了强化蒸气的滴状冷凝传热，通过考察正硅酸乙酯含量，氨水含量等条件的影响，制备出了具有超疏水表面的PVDF复合塑料换热管。结果表明，所制备的换热管表面接触角可达154°，与熔融法及NIPS法制备的换热管相比，总传热系数可提高85.3%～147.3%。     

Preparation of superhydrophobic surfaces by cauliflower‐like polyaniline

Cauliflower‐like polyaniline (PANI) was successfully prepared using an interfacial polymerization method. By modification with polydimethylsiloxane (PDMS) using chemical vapor deposition method, the surface wettability of cauliflower‐like PANI can be tailored to be superhydrophobic with a water contact angle of 160.4°. The deposition of the low‐surface‐energy silicon coating originated from PDMS pyrolysis on the cauliflower‐like PANI was confirmed by X‐ray photoelectron spectroscopy and Fourier Transform Infrared Spectroscopy. The changes in thermal stability and conductivity of the as‐prepared PANI before and after PDMS treatment were also investigated by thermogravimetric analysis and using a four‐probe method. Compared with nanofiber‐shaped PANI by electrodepositing polymerization, the PDMS‐treated cauliflower‐like PANI has superior surface wettability. Our study may open a new way for fabrication of superhydrophobic surfaces by developing novel nanostructured PANI. © 2013 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014 , 131, 39767.     

Modification of polydimethylsiloxane with polyvinylpyrrolidone: Influence of reinforcing filler on physico‐mechanical properties

The present article reports an approach for the modification of hydrophobic polydimethylsiloxane (PDMS) with low molecular weight hydrophilic polyvinylpyrrolidone (PVP) via solution blending method to develop new PDMS‐based materials with improved mechanical performance and wettability which can be used in many biomedical applications. The influence of dimethyldichlorosilane treated fumed silica (FS) on physico‐mechanical properties of PDMS–PVP blends were investigated and analyzed. There was the significant improvement in mechanical, dynamic mechanical and thermal properties of PDMS–PVP blends, whereas, transparency and contact angle were slightly decreased after incorporation of FS into PDMS–PVP blends. Scanning electron microscopy revealed that the fourfold reduction in the average domain size of the dispersed PVP in the PDMS matrix in the presence of compatibilizer (PDMS‐PEO block copolymer) when compared with the uncompatibilized PDMS–PVP blend morphology. By incorporation of FS into the neat PDMS matrix, the onset of degradation (T_i), the maximum rate of degradation (T_max) and overall thermal stabilities increased significantly. On the other hand, by the addition of FS into to PDMS–PVP blends, the T_i and T_max remains unaffected, but overall thermal stabilities increased significantly. PDMS–PVP blends exhibited low contact angle (～45°) which confirmed the formation of the hydrophilic surface. POLYM. ENG. SCI., 56:491–499, 2016. © 2016 Society of Plastics Engineers     

A durable and environmental friendly superhydrophobic coatings with self-cleaning,anti-fouling performance for liquid-food residue reduction

A durable and environmentally-friendly superhydrophobic coatings for liquid-food residue reduction were prepared by using stearic acid (SA) modified organic montmorillonite (SA@OMMT) and poly(dimethylsiloxane) (PDMS). Due to the natural hydrophobicity of SAs, SA@OMMT provides low surface energy as well as roughness for the coating. PDMS not only provided low surface energy in the coating but also contributed to the bonding of SA@OMMT as a result of its high adhesive properties. In addition, PDMS has good physical properties after curing, which can effectively improve the physical properties and durability of a superhydrophobic coating by the self-assembly method using a PDMS/n-hexane solution. For 1 wt.% SA@OMMT and 5 wt.% PDMS, the resulting SA@OMMT/PDMS (SOP) coating showed the water contact angle (WCA) and water sliding angle (WSA) of 156.3°and 2°, respectively. The prepared coatings have good physical and chemical stability, and they still have superhydrophobicity after physical abrasion tests and exposure to the corrosion solutions. In the meanwhile, the prepared coating also has flexibility and superhydrophobicity after bending and folding. Finally, the coating surface shows highly effective antifouling ability to liquid and solid pollutants. The coating can be applied against different substrates and has potential application in the field of liquid-food residue reduction.     

基于聚二甲基硅氧烷制备超疏水表面的研究进展

聚二甲基硅氧烷(PDMS),作为一种价格低廉、环境友好的有机硅材料,被广泛作为超疏水修饰剂来使用,并利用其与固化剂混合后可固化成型的特点,用于构建表面结构。综述了PDMS在制备超疏水材料上的研究进展,并对其今后的发展做出了展望。     

Polydimethylsiloxane assisted supercritical CO2 foaming behavior of high melt strength polypropylene grafted with styrene

Foamable high melt strength polypropylene (HMSPP) was prepared by grafting styrene (St) onto polypropylene (PP) and simultaneously introducing polydimethylsiloxane (PDMS) through?a?one-step?melt extrusion process. The effect of PDMS viscosity on the foaming behavior of HMSPP was systematically investigated using supercritical CO₂ as the foaming agent. The results show that the addition of PDMS has little effect on the grafting reaction of St and HMSPP exhibits enhanced elastic response and obvious strain hardening effect. Though the CO₂ solubility of HMSPP with PDMS (PDMS-HMSPP) is lower than that of HMSPP without PDMS, especially for PDMS with low viscosity, the PDMS-HMSPP foams exhibit narrow cell size distribution and high cell density. The fracture morphology of PDMS-HMSPP shows that PDMS with low viscosity disperses more easily and uniformly in HMSPP matrix, leading to form small domains during the extrusion process. These small domains act as bubble nucleation sites and thus may be responsible for the improved foaming performance of HMSPP.     

Preparation of oil-water separation network based on the novel strategies of SiO2 ceramic micro-nano structure and PDMS modification

In this study, we adopted the novel strategies of the soot template method to construct SiO₂ ceramic micro-nano structure surface and polydimethylsiloxane (PDMS) modification to reduce the surface energy. We fabricated a superhydrophobic/superoleophilic NS-PDMS oil–water separation screen by depositing coarse nano-SiO₂ ceramic on the surface of 100-mesh stainless-steel screen used as a substrate under the soot template method, which reduced the surface energy with PDMS. The fabricated NS-PDMS screen exhibited excellent superhydrophobic and self-cleaning properties. In particular, the superhydrophobic properties were stably maintained under various harsh conditions. Overall, the screen manifested self-cleaning ability for various water-containing stains, for example, coffee, milk, beer, and soy sauce. The mechanically damaged screen surface still retained its high roughness, and re-modification with PDMS could recover the superhydrophobic surface and oil–water separation performance. This suggests the re-use potential of the damaged NS-PDMS screen, which is vital for cost reduction and resource recycling. We believe that our study makes a significant contribution to the literature, because the fabricated NS-PDMS screen is superhydrophobic, superoleophilic, resistant toward several water-based solutions, chemically and mechanically stable under certain conditions, and can be reused with modification and repair after damage. Therefore, this screen can be broadly used as an oil–water separator.     

纳米ZnO改性PLA/PBS及其发泡体系的性能

采用熔融共混法制备了纳米氧化锌(ZnO)填充聚乳酸/聚丁二酸丁二酯(PLA/PBS)复合材料。研究了ZnO质量分数对复合材料的力学性能、结晶性能以及动态流变性能的影响。结果表明,随着ZnO含量的增加,复合材料的力学性能和结晶度先升高后降低,当ZnO质量分数为0.5%时,复合材料的拉伸强度和冲击强度分别达到最大值40.99 MPa和8.82 k J/m~2,比未添加ZnO时分别提高了6.3%和28.2%,同时结晶度达到24.4%。动态流变性能测试表明,ZnO的质量分数为0.5%时,复合材料的损耗模量和储能模量均为最大值,反映出此时复合材料内部氢键和交联网络最完善,协同作用效果达到最佳状态,因此力学性能也最优。在ZnO质量分数为0.5%的基础上,采用超临界二氧化碳发泡法对复合材料进行间歇发泡,结果显示添加ZnO的发泡材料泡孔密度比未添加的高出一个数量级,泡孔尺寸分布更加集中,体积膨胀率更高。     

聚芴醚酮超疏水喷涂纸及其性能

以聚二甲基硅氧烷(PDMS)和纳米SiO2掺杂聚芴醚酮(PFEK),采用溶液喷涂法在纸张表面构筑了耐用的超疏水涂层.考察了PDMS和SiO2用量(以PFEK和N-甲基吡咯烷酮的质量为基准,下同)对纸张水接触角的影响.结果表明,当PDMS和SiO2用量均为2％时,纸张表面的水接触角达到最大值170?,滚动角最小值为1?,...     

微孔发泡聚苯乙烯力学性能的分析与探讨

制备了发泡量相同的微发泡聚苯乙烯,采用扫描电镜(SEM)和Image-pro图像处理软件对微发泡聚苯乙烯的微孔尺寸进行了观察和统计;建立微球模型,分析了微孔尺寸大小对微发泡聚苯乙烯力学性能的影响.结果表明:细小而均匀的泡孔对微发泡聚苯乙烯力学性能的提高有较明显的促进作用,微球模型的计算结果与宏观力学性能的影响规律有很好的重现性.     

A comparative study of superhydrophobicity of 0D/1D/2D thermally functionalized carbon nanomaterials

Superhydrophobic coatings promise various practical applications. A one-step, ingenious yet economical thermal curing method is devised to render the carbon nanomaterials superhydrophobic. This study aims to compare the degree of superhydrophobicity of the carbon/polydimethylsiloxane (PDMS) synthesized from the 2D graphene nanoplatelets (GNPs), 1D multiwalled carbon nanotubes (MWCNTs), and 0D carbon black (CB) nanomaterials. The superhydrophobic GNPs/PDMS, MWCNTs/PDMS and CB/PDMS are synthesized when thermally functionalized with the siloxane groups. The Fourier transform infrared spectroscopy data signifies the successful functionalization of the carbon nanostructures by siloxane chains and the Raman spectroscopy analyses indicate that GNPs/PDMS manifests the highest degree of structural defects due to functionalization. The degree of superhydrophobicity induced on the carbon/PDMS coatings correlates with the dimensions of the carbon nanomaterials (0D, 1D and 2D), which is intimately associated with the effective surface areas of the nanomaterials susceptible of chemical functionalization. The promising applications of the superhydrophobic coatings are demonstrated. This study proposes a novel wettability tuning method and provides insightful analyses and characterization of the superhydrophobicity of the thermally functionalized carbon nanomaterials with different dimensions of varied nano-geometries.     

加工参数及配方对PP/SBS共混物泡孔形态的影响

以CO2为发泡剂,利用SEM、DSC等测试方法研究了聚丙烯/苯乙烯-丁二烯-苯乙烯共聚物(PP/SBS)共混物的发泡行为。结果表明:在PP基体中引入SBS能显著改善发泡样品的泡孔形态;引入聚二甲基硅氧烷(PDMS)后,共混物的泡孔尺寸降低,泡孔密度进一步增大;在高压力降速率下,共混物的泡孔形态进一步改善;当发泡温度降到105℃时,由于CO2的增塑作用,PP/SBS/PDMS共混物仍能充分发泡,而且泡孔结构更好,其泡孔密度3.4×109个/cm3,平均泡孔直径6μm左右。     

In vitro blood compatibility of modified PDMS surfaces as superhydrophobic and superhydrophilic materials

The surface of polydimethylsiloxane rubber (PDMS) was irradiated by a CO₂‐pulsed laser. The irradiated surfaces were grafted by hydroxyethylmethacrylate phosphatidylcholine (HEMAPC) by using the preirradiation method. The laser‐treated surfaces and HEMAPC‐grafted PDMS surfaces were characterized by using a variety of techniques including ATR‐FTIR spectroscopy, scanning electron microscopy (SEM), and wettability, which was measured by a water‐drop contact angle. Different surfaces with different wettability were prepared. These surfaces, including untreated PDMS (hydrophobic), laser‐treated PDMS (superhydrophobic), and HEMAPC‐grafted surfaces (superhydrophilic), were used for a platelet adhesion study. Results from in vitro testing indicated that chemical structures, such as negative‐charge polar groups and wettability, are important factors in blood compatibility of these surfaces and the superhydrophilic (the most wettable) and the superhydrophobic (the most unwettable) of modified PDMS surfaces have excellent blood compatibility compared to the unmodified PDMS. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 91:2042–2047, 2004     

Poly dimethylsiloxane/carbon nanofiber nanocomposites: fabrication and characterization of electrical and thermal properties

This article presents the fabrication and characterization of poly dimethylsiloxane/carbon nanofiber (CNF)-based nanocomposites. Although silica and carbon nanoparticles have been traditionally used to reinforce mechanical properties in PDMS matrix nanocomposites, this article focuses on understanding their impacts on electrical and thermal properties. By adjusting both the silica and CNF concentrations, 12 different nanocomposite formulations were studied, and the thermal and electrical properties of these materials were experimentally characterized. The developed nanocomposites were prepared using a solvent-assisted method providing uniform dispersion of the CNFs in the polymer matrix. Scanning electron microscopy was employed to determine the dispersion of the CNFs at different length scales. The thermal properties, such as thermal stability and thermal diffusivity, of the developed nanocomposites were studied using thermogravimetirc and laser flash techniques. Furthermore, the electrical volume conductivity of each type of nanocomposite was tested using the four-probe method to eliminate the effects of contact electrical resistance during measurement. Experimental results showed that both CNFs and silica were able to impact on the overall properties of the synthesized PDMS/CNF nanocomposites. The developed nanocomposites have the potential to be applied to the development of new load sensors in the future.     

PF/PDMS-OH流变性能对其泡沫材料泡孔结构的影响

分别将质量分数为10%,15%和20%的端羟基聚硅氧烷(PDMS–OH)通过机械共混的方法改性酚醛树脂(PF),进而采用化学发泡的方法制备PF/PDMS–OH泡沫复合材料。采用旋转式流变仪表征共混体系的稳态及动态流变性能,研究黏弹性对树脂发泡过程的影响。傅立叶变换红外光谱表征PDMS–OH与树脂在固化过程中的化学反应。扫描电镜表征不同共混体系下泡孔的结构与形态。结果表明,加入15%PDMS–OH的共混体系具有最利于发泡成型的黏弹性,且可与PF形成化学交联作用,对PF泡沫的泡孔形态影响显著。同时红外表征显示,PDMS–OH与PF在固化过程中发生化学交联,这种互穿交联网状结构为PF及泡沫提供了更多稳定的柔性链段。     

Effect of the introduction of polydimethylsiloxane on the foaming behavior of block‐copolymerized polypropylene

We investigated the effect of polydimethylsiloxane (PDMS) on the foaming properties of block‐copolymerized polypropylene (B‐PP) by blending different contents of PDMS with B‐PP in the extrusion process using supercritical CO₂ as the blowing agent. The experimental results indicate that the addition of PDMS greatly increased the expansion ratio of the foamed samples. At the same time, the cell population density of foams obtained from the blends also increased to a certain degree and provided a new perspective on improving B‐PP's foaming performance. The addition of PDMS also decreased the die pressure because of the reduced viscosity of the B‐PP/PDMS blends compared with that of the B‐PP matrix. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2012