指状和海绵状聚偏氟乙烯多孔膜的制备及表征

利用倒相法在纯水和φ(ethano l)=20%、φ(ethano l)=40%的乙醇/水凝胶浴中分别制备了聚偏氟乙烯(PVDF)多孔膜,通过SEM,DSC对这些薄膜进行了分析表征。结果表明纯水凝胶浴中所成膜为指状多孔膜,随着凝胶浴乙醇体积分数的增加,膜指状大孔逐渐消失,在φ(ethano l)=40%的乙醇/水凝胶浴中转变为海绵状多孔膜;指状多孔膜和海绵状多孔膜熔点相对于原料分别提高了3.9℃和3.5℃,而结晶度相对于原料分别提高了16.1%和13.5%。对成膜机理和结晶度变化的原因进行了分析。     

呼吸图案法制备高分子有序多孔膜的研究进展

主要综述了呼吸图案法制备高分子有序多孔膜的国内外研究进展,分析了多孔膜的形成过程和机理;着重讨论了环境湿度、非水气氛、溶剂种类、聚合物浓度、温度、基底和聚合物结构等因素,对呼吸图案法制备有序多孔膜的形貌和孔径尺寸的影响;分析了呼吸图案法制备有序多孔膜的改进方法以及有序多孔膜的应用,并对其未来的发展提出了展望。有序多孔膜的形成机理、纳米级小孔径的制备、大面积有序多孔膜的制备以及多孔膜智能化,将是呼吸图案法制备高分子有序多孔膜的主要研究方向。     

淬冷速率对聚氨酯多孔膜形态结构的影响

采用热致相分离（TIPS）技术制备了聚氨酯（PU）多孔膜，研究了成膜平台温度对多孔膜表面形态，孔度大小，孔隙率和透湿率的影响，在不同成膜温度下制备的PU多孔膜的共同特征是底面（与成膜平台的接触面）光滑平整，孔洞的尺度小于相应的表面（与空气的接触面），断面结构显示，PU多孔膜的内部疏松而多孔，孔之间相互连通，且存在较为规则的梯形条纹状（Ladder-like)结构，以寻热性较差的玻璃代替不锈钢成膜平台，在相同的条件下所得多孔膜的孔度，了忆隙率和透湿率明显增大，通过控制成膜温度，成膜平台材质等制备条件，可对PU多孔膜的形态结构，孔度大小，孔隙率和透湿率等性能进行剪裁。     

ZnO多孔纳米固体厚膜气敏传感器的制备和性质表征

以ZnO纳米粉(平均粒径30nm)为原料,利用水热热压方法制备了多孔的ZnO体块纳米固体,测试了以多孔纳米固体为原料制成的厚膜气敏传感器对挥发性有机化合物(VOCs)乙醇、丙酮、苯、甲苯和二甲苯蒸气的气敏特性,并与用ZnO纳米粉制备的厚膜传感器进行了比较.结果发现,与ZnO纳米粉相比,用ZnO多孔纳米固体制备的厚膜传感器在空气中的电阻大大减小,最佳敏感温度降低、响应时间和恢复时间大大缩短.通过综合分析ZnO纳米粉和ZnO多孔纳米固体的XRD、TEM及厚膜传感器的SEM测试结果研究了厚膜传感器气敏特性的差异.     

过氯乙烯多孔膜的制备、性质及近红外反射性能研究

本文利用溶剂挥发法制备过氯乙烯多孔膜，通过调整沉淀剂的用量和种类，可以控制多孔膜的结构和尺寸。通过电镜观察了其多孔结构，研究了沉淀剂用量和种类对膜孔性质的影响，并分析了膜的近红外反射性能，发现微孔结构的存在可以大大提高过氯乙烯膜的近红外反射性能。     

铝阳极氧化膜的扩孔处理

铝多孔质阳极氧化膜是制备自润滑阳极氧化铝的基础，其技术关键之一是在不破坏氧化膜结构与性能的前提下，尽可能扩大微细孔的孔径。本文用透射电镜（ＴＥＭ）、显微硬度仪、ＳＲＶ摩擦实验机等设备，系统考察了草酸溶液中生成铝阳极氧化膜的微观多孔质结构以及经扩孔处理后该氧化膜多孔质结构的变化和对氧化膜机械性牟的影响，重点探讨了扩孔处理对氧化膜表面硬度和耐磨性的影响，并由此确定了最佳扩孔时间及最佳孔径，为制备纳米量     

水滴模板法制备蜂窝状结构多孔膜的研究进展

水滴模板法制备蜂窝状结构多孔膜是图案化表面技术领域的一大进展，其在生物技术、组织工程等领域有可能获得重要应用。综述了水滴模板法制备蜂窝状结构多孔膜的国内外研究进展，着重阐述了蜂窝状多孔膜的制作方法、形成机理及影响因素，同时指出了目前研究中存在的主要问题，并进一步提出了未来的研究发展方向。     

聚乳酸-乙醇酸共聚物/丝素共混纳米纤维多孔膜的制备及性能

以六氟异丙醇（HFIP）为共溶剂,通过静电纺丝法制备了聚乳酸-乙醇酸共聚物（PLGA）/丝素（SF）共混纳米纤维多孔膜。用场发射扫描电镜（FE-SEM）、傅立叶红外光谱分析仪（FT-IR）、多功能拉伸仪、液滴形状分析仪对共混纤维多孔膜的形貌、分子结构、力学性能及亲水性进行测试。结果表明,共混多孔膜中随SF的加入纤维直径...     

纯沸石膜制备及表征

在多孔陶瓷载体上制备过渡层，再以水热法合成出ＺＳＭ－５型沸石膜，经扫描电镜测定，膜厚１２μｍ，过渡层厚１３．８μｍ。将ＺＳＭ－５沸石膜用于乙醇水渗透蒸发分离，分离因数为１５，这时其渗透通量为０．４６ｋｇ／ｍ＾２．ｈ．。     

相转化法制备聚羟基丁酸戊酸酯多孔膜EI北大核心CSCD

以二甲基乙酰胺(DMAc)作为溶剂,采用相转化法制备聚羟基丁酸戊酸酯(PHBV)平板多孔膜,通过对非溶剂、铸膜液浓度、凝固温度、凝固浴组成的调节,调控成膜过程中的相分离行为,制备出结构可控的PHBV多孔膜。研究表明,45℃时PHBV/DMAc/H_2O体系分相比PHBV/DMAc/乙醇体系更快。当凝固浴为纯水时,非溶剂和溶剂交换速率快,发生瞬时分相,而PHBV固化速率较低,多孔膜形貌呈指状孔、海绵孔并存。随着凝固浴中溶剂DMAc的加入,非溶剂和溶剂的交换速率变缓,从而发生延时分相,多孔膜呈均匀的海绵状结构。     

新型管式炭载体上Sukucalite-1型沸石复合膜的制备与性能

以多孔炭管为载体,采用预涂晶种二次生长法在澄清溶液体系制备了炭基-Silicalite-1沸石复合膜.XRD、SEM及气体渗透性能表明合成的炭基-沸石复合膜完整、致密,在室温下,H2/C3H8的理想分离因数达到了13.6,显示出明显的分子筛分性能.沸石直接在无晶种层的炭表面上不易生长成膜,而具有晶种层的炭表面可形成连续沸石膜.用弱极性的乙醇代替常规的水作为晶种溶剂可有效地将晶种引入到非极性的炭表面而形成连续、均匀的晶种涂层.在氮气气氛、793K下焙烧,可以除去复合膜中的有机胺模板剂,并避免炭载体结构的氧化破坏.     

新型管式炭载体上Silicalite-1型沸石复合膜的制备与性能

以多孔炭管为载体, 采用预涂晶种二次生长法在澄清溶液体系制备了炭基- Silicalite-1沸石复合膜. XRD、SEM及气体渗透性能表明: 合成的炭基-沸石复合膜完整、致密, 在室温下, H₂/C₃H₈ 的理想分离因数达到了13.6, 显示出明显的分子筛分性能. 沸石直接在无晶种层的炭表面上不易生长成膜, 而具有晶种层的炭表面可形成连续沸石膜. 用弱极性的乙醇代替常规的水作为 晶种溶剂可有效地将晶种引入到非极性的炭表面而形成连续、均匀的晶种涂层. 在氮气气氛、793K下焙烧, 可以除去复合膜中的有机胺模板剂, 并避免炭载体结构的氧化破坏.     

Plasma-treated polyethersulfone coated with crosslinked poly(vinyl alcohol): composite membranes for pervaporation dehydration of ethanol

Composite membranes with crosslinked poly(vinyl alcohol) matrix as selective layer coated on a polyethersulfone supporting porous layer were prepared aiming at separating ethanol/water mixtures by pervaporation. A polyethersulfone asymmetric microporous membrane was synthesized by the wet phase inversion process. The support membrane was then exposed to air plasma to activate the surface. The selective dense layer was obtained by coating of PVA and a crosslinking agent over the polyethersulfone substrate, followed by thermal treatment. The morphology was examined by scanning electron microscopy (SEM) for both, support membrane and the coated polymeric layers. Surface physicochemical properties were evaluated through measuring the contact angle (θ) and the estimation of surface free energy (γ_S) and adhesion work. The surface chemical composition of support membrane and coated hydrophilic layers were characterized by infrared spectra with horizontal attenuated total reflectance (FT-IR/HATR). The swelling degree of PVA dense membranes, and the pervaporation performance of the crosslinked PVA/PES composite membranes, manufactured with several coating steps, were evaluated with water/ethanol (20/80 wt%) mixtures at temperatures in the range of 30–60 C. Results of the effective pervaporation dehydration of ethanol are discussed in terms of membrane morphology and the solution-diffusion transport mechanism.     

高通量ZSM-5填充硅橡胶复合膜渗透汽化性能研究

以硅铝比为360的ZSM-5型沸石对聚二甲基硅氧烷(PDMS)进行填充,以聚偏氟乙烯(PVSF)为支撑层,制备了ZSM-5填充PDMS/PVDF复合膜,用于渗透汽化乙醇/水混合物的分离.研究了沸石填充量、操作温度、进料液浓度对乙醇/水的渗透汽化分离性能的影响,发现该复合膜较文献报道中的沸石填充膜,其渗透通量有了明显的提高,在50℃沸石填充量为40%时,对乙醇的分离因子为11.7,其渗透通量达到749.8 g/(m2·h).随着操作温度的升高或料液中乙醇浓度升高,渗透通量增大,分离因子下降.     

Porous Cube-like In2O3 Nanoparticles and Their Sensing Characteristics toward Ethanol

Porous cube-like crystalline In2O3 nanoparticles with an average diagonal length of 34.8 nm were fabricated by a laser ablation-reflux process to form In（OH）3, followed by a calcination treatment to yield porous In2O3. HRTEM （high-resolution transmission electronic microscopy）, XRD （X-ray diffraction）, BET （Brunauer-Emmett-Teller）, and XPS （X-ray photoelectron spectroscopy） analysis were used to characterize their crystalline structures, grain sizes, surface areas, and surface compositions. The as-prepared porous in-dium oxides were tested for their sensing properties toward ethanol. Non-porous In2O3 nanopowder （about 40 nm） was also examined in order to compare the results with the as-prepared porous In2O3 nanomaterials. The porous In2O3 exhibited much better performance than that of non-porosus In2O3, and showed enhanced sensitivity with a lower detection limit than other reported In2O3-based materials when exposed to ethanol. Good gas sensitivity and linear behavior as a function of ethanol concentration were observed in the porous In2O3 nanoparticles.     

Facile synthesis of porous ZnO microbelts and analysis of their gas-sensing property

Porous ZnO microbelts were achieved using a facile chemical solution method combined with subsequent calcination. The micro-nanostructures were characterized through X-ray diffraction, field emission scanning electron microscopy, thermogravimetric-differential thermal analysis, and Brunauer–Emmett–Teller N₂ adsorption-desorption analyses, among others. The BET surface area of the porous ZnO microbelts was calculated at 23.0 m² g⁻¹. Furthermore, the gas sensing properties of the as-prepared porous ZnO microbelts were investigated using volatile organic compounds. Compared with ZnO microflowers, the porous ZnO microbelts exhibited higher response with certain organic vapors, such as formaldehyde, acetone, and ethanol. The responses to 100 ppm formaldehyde, acetone, and ethanol were 45.7, 40.6, and 38.4, respectively, at a working temperature of 300 °C. The results showed that the porous ZnO microbelts are highly promising candidates for gas sensing applications.     

表面喷涂壳聚糖溶液对聚偏氟乙烯多孔膜的结构和性能的影响

在聚偏氟乙烯(PVDF)溶液膜表面喷涂壳聚糖(CS)醋酸溶液,用浸没相转变法制备PVDF多孔膜,研究CS溶液对多孔膜的结构和性能的影响并探讨了成膜机理。结果表明,随着溶液膜表面CS溶液体积的增加PVDF膜的孔隙率提高,膜表面的亲水性大幅度提高,β晶含量降低而α晶的含量提高;喷涂CS溶液前PVDF膜的上表面结构致密,喷涂CS溶液后PVDF膜上表面呈现多孔结构,其断面结构均为指状大孔结构;喷涂CS溶液的体积为2 mL、4 mL和6 mL的PVDF膜,其水通量先增加后降低,分别为683.33 L/m²·h、1121.57 L/m²·h、1171.36 L/m²·h和1029.02 L/m²·h。用不同方法制备的PVDF膜,其结构和性能不同,因为膜上表面的成膜机理不同。     

Performance of ethanol electro-oxidation on Ni-Cu alloy nanowires through composition modulation

To reduce the cost of the catalyst for direct ethanol fuel cells and improve its catalytic activity, highly ordered Ni-Cu alloy nanowire arrays have been fabricated successfully by differential pulse current electro-deposition into the pores of a porous anodic alumina membrane (AAMs). The energy dispersion spectrum, scanning and transmission electron microscopy were utilized to characterize the composition and morphology of the Ni-Cu alloy nanowire arrays. The results reveal that the nanowires in the array are uniform, well isolated and parallel to each other. The catalytic activity of the nanowire electrode arrays for ethanol oxidation was tested and the binary alloy nanowire array possesses good catalytic activity for the electro-oxidation of ethanol. The performance of ethanol electro-oxidation was controlled by varying the Cu content in the Ni-Cu alloy and the Ni-Cu alloy nanowire electrode shows much better stability than the pure Ni one.     

Synthesis and gas sensing properties of novel SnO2 nanorods

We report the microstructures and gas sensing properties of two novel SnO₂ nanorods prepared by hydrothermal method with the utilizing of cetyltrimethylammonium bromide and polyethylene glycol. The structures and morphologies of the dense and porous nanorods were characterized by means of powder X-ray diffraction and scanning electron microscopy. The gas sensing performances towards ethanol of the two samples were investigated. The results show that the porous SnO₂ nanorods display excellent gas response to ethanol, indicating SnO₂ as a potential gas sensing material for broad applications.     

高强度复合型PVDF中空纤维膜的制备研究（Ⅱ）凝固浴及纤维数对膜性能的影响

通过改变乙醇溶液凝固浴中乙醇含量及纤维增强层中涤纶纤维支数,详细研究了这两方面因素对于高强度复合型PVDF中空纤维膜的影响.研究表明,凝固浴组成可有效控制涂膜层分相速度,进而影响自身结构及润湿性能,对膜整体渗透及强度性能产生影响.而纤维则是强度功能的主要承担者,支数增大,对强度性能有明显提高.利用纤维编织层增强PVDF中空纤维膜切实可行,效果明显.