聚丙烯核孔膜化学蚀刻工艺研究

探讨了蚀刻剂中重铬酸钾浓度、硫酸浓度及蚀刻温度、蚀刻时间等因素对聚丙烯膜基体蚀刻速率的影响；建立了基体蚀刻速率与重铬酸钾浓度，硫酸浓度、蚀刻温度的数学关联式；并选择一定的蚀刻条件对辐照过的聚丙烯膜进行蚀刻，得到了预期孔径的聚丙烯核孔膜。     

PET核孔膜蚀刻速率影响因素的研究

核孔膜是通过重离子照射薄膜后进行化学蚀刻所得到的高性能过滤材料,蚀刻速率是影响高质量核孔膜制备的重要因素。本文探讨了不同蚀刻液浓度、温度以及重离子辐照能量对蚀刻速率的影响。利用140 MeV的32S离子在室温和真空条件下对4层堆叠的PET(polyethylene terephthalate)薄膜进行了辐照。在对辐照样品进行化学蚀刻期间采用电导法确定了径迹蚀刻速率Vt。结果表明:蚀刻速率与蚀刻温度呈指数相关,随蚀刻液浓度增加而线性增大;径迹蚀刻速率随能量损失率(离子能损)增大。研究确定,在入射32S能量为1.6 MeV·u-1时,NaOH浓度为1mol·L-1、蚀刻温度为85°C时最有利于形成圆柱形微孔。     

核孔膜孔径测量和过滤效果研究

利用兰州重离子加速器提供的25 MeV·u~(-1) ~(86)Kr~(26+)离子辐照厚度为12μm和25μm的聚对苯二甲酸乙二酯(Poly(ethylene terephthalate),PET)薄膜,注量分别为1×10~6 ions·cm~(-2)和5×107 ions·cm~(-2)。将辐照后的PET薄膜浸入5 mol·L~(-1)、60oC的NaOH溶液蚀刻,制得不同孔径的核孔膜样品。分析了测厚法、光学显微镜观察法和泡点法三种孔径测量法的优劣,实验对比结果表明,对于孔径小于1μm的纳米孔径核孔膜,适合利用泡点分析法测量有效截留孔径,测量误差小于5%;对于孔径大于3μm的微米孔径或直筒孔核孔膜,优先选择光学显微镜观察法测量表面孔径,测量误差小于10%。制备孔径为2μm和450 nm的核孔膜样品,用其进行黄河水过滤,探究过滤效果。进一步证明微米孔径核孔膜去除水样中一般颗粒物有明显效果(微粒数目平均减少99.12%),450 nm孔径或更小孔径的核孔膜可绝大部分清除水样中的细菌(微粒数目减少99.90%)。实验结果对今后核孔膜孔径的测量和定标及水质净化具有参考意义。     

电导法研究紫外光预辐照对核孔膜径迹蚀刻的影响

利用紫外光辐照聚碳酸酯（PC）离子径迹膜,研究光辐照对于核孔膜蚀刻过程的影响。实验结果显示,紫外光照射对核孔膜的蚀刻有着重要的作用,它可以有效地增加径迹的蚀刻速率,并且径迹蚀刻速率随紫外光照时间的增加呈线性增长关系,此现象是由于光降解作用引起的。本文还介绍了用于监测核孔膜蚀刻过程的电导测量方法,利用此方法可以得出核孔膜径迹蚀刻速率、孔径随蚀刻时间变化等关系。     

聚酯膜在NaOH溶液中的蚀刻速率

木文研究了蚀刻剂对聚酯(PET)基膜的蚀刻速率及径迹蚀刻速率,以制备精确孔径的核孔膜。测定了PET基膜在不同浓度、温度的NaOH溶液中的蚀刻速率,经回归得到它们之间的经验关联式,提出了几种增大PET膜径迹蚀刻速率的有效方法。     

聚碳酸酯和聚酯核孔膜的性能研究

聚碳酸酯(Polycarbonate,PC)和聚对苯二甲酸乙二酯(Polyethylene Terephthalate,PET)薄膜因其可被碱性溶液有效刻蚀而被用于核孔膜材料。采用11.4 MeV·u-1的Au离子和20 MeV·u~(-1)的Kr离子分别辐照PC及PET薄膜,然后经NaOH溶液蚀刻,制得膜孔径分别为20-400 nm和100-700 nm的PC和PET核孔膜。扫描电子显微镜(Scan Electron Microscope,SEM)和气-液排除法等表征和测试结果显示孔密度与辐照剂量有关;蚀刻时间越长,膜孔径越大,实验制备的核孔膜孔分布越均匀。被辐照后的PET膜亲水性比PC膜高。在0.15 MPa和室温下,水溶液中的牛血清白蛋白(Bovine Serum Albumin,BSA)可被不同孔径的PET核孔膜有效截留;膜孔径越小,截留率越高,过滤所需压力越大,膜越易被污染。     

纳米孔径重离子微孔膜的制备

应用中国原子能科学研究院HI 13串列加速器产生的重离子32S和79Br轰击聚对苯二甲酸乙二醇酯（PET）薄膜,再对薄膜进行化学蚀刻处理使由重离子辐照损伤产生的潜径迹形成微孔,制备出孔径为100～900nm的重离子微孔膜。为增加径迹蚀刻速率与体蚀刻速率之比,化学蚀刻前采用紫外光辐照薄膜。蚀刻过程中采用电导蚀刻法监测膜孔径生长过程。对32S和79Br辐照制备的重离子微孔膜进行了比较,79Br离子辐照制备的微孔膜与32S离子辐照制备的微孔膜相比,孔型圆整,锥角更小;在制备纳米微孔膜方面79Br离子优于32S离子。     

电子束辐照制备微孔阵列聚丙烯膜的研究

采用电子束辐照方法成功制备了微孔阵列聚丙烯(PP)膜,将微孔阵列掩膜覆盖在聚丙烯膜上,在电子束下进行辐照,然后将样品在蚀刻剂中进行蚀刻,即可得到微孔阵列聚丙烯膜,其孔径为200μm.在研究中采用XRD、GPC、DSC等仪器分别测定了不同剂量辐照的PP样品的结晶度和分子量,分析了它们可能存在的内在联系及其对蚀刻工艺的影响,并对不同方法测得的结晶度结果进行了对比;探讨了蚀刻时间、蚀刻温度、蚀刻剂浓度等因素对蚀刻结果的影响;使用电子拉力机测定了不同电子束辐照剂量PP膜的力学性能;采用电子显微镜对制备的微孔阵列聚丙烯膜图案和孔径进行了相关表征.     

外加高频电场对核径迹化学蚀刻过程及微孔形态影响研究

为研究聚对苯二甲酸乙二醇酯（PET）单面蚀刻的详细过程,利用自制蚀刻装置的电流信号对核孔膜单面蚀刻过程进行监测。对装置的本底电流进行研究分析,发现本底电流主要由装置中的电容控制,受膜厚影响,与温度无关。利用装置的电流信号对蚀刻过程进行了记录,根据电流信号的变化可将整个蚀刻过程分为3个阶段。综合研究了外加高频交流电场的有无及强度对蚀刻过程、通孔时间及核孔膜微孔孔形的影响。发现高频交流电场的存在使通孔时间缩短;在相同的蚀刻条件下,孔形更接近柱形,且这两种作用随着电场强度的增加而加强,并在10V/cm的电场强度附近时达到饱和。     

核径迹微孔滤膜的制备及其在水样分析中的应用

1.制备方法 在真空靶室中用原子能所反应堆的热中子使~(235)U裂变,将产生的裂片准直后射入一定厚度的聚碳酸酯膜(朝阳塑料厂生产)中,照射过的膜浸入温热的氢氧化钠溶液中蚀刻,形成穿透膜的圆柱形孔洞,冲洗、晾干,得到核孔滤膜。控制蚀刻时间和照射时间可以得到各种孔径(0.6～8μm)和孔密度(1×10~5～5×10~7/cm~2)的核孔滤膜,膜直径为13～142mm。     

Factors Affecting Etching Properties of CR-39 Detector for Alpha-Particles

Several factors affecting the track registration performance of CR-39 detectors were studied, adopting as intermediate criterion of detector performance the diameters of etch pits left by normally-incident α-particles. Measures that have been proposed for enhancing detector performance, such as stirring and by ultrasonic vibration applied during etching have proved not to be effective: While these measures increased the etch pit diameters to some extent, the same measures were found to accelerate in keeping also the bulk etching rate, so that the increase observed in the etch pit diameters could not be attributed to enhancement of track registration sensitivity, which is the ultimate criterion of detector performance. Contamination of detector surface with finger grease transferred upon manipulation with bare hand proved not to influence even the intermediate criterion of etch pit diameter. Nor was this criterion influenced by the presence in etchant solution of etched products up to a concentration of 5 g/l. On the other hand, the etch pit diameters were found to be influenced beyond negligible extent by environmental factors such as humidity and temperature even within the range of normal variations occurring in the natural environment, and these factors thus require taking into account in order to ensure consistent measurements with CR-39 detector.     

Investigation of initial stage of chemical etching of ion tracks in polycarbonate

Chemical track etching and the growth of nanochannels in ion-irradiated polycarbonate foils were investigated by loss of weight measurements and IR-spectroscopy. The data provided by both methods are in good agreement and allow us to shed light on the early stage of pore formation including times where the breakthrough of the pores has not yet occurred. Clear evidence is shown that the pore growth as a function of etching time depends on the irradiation fluence. For fixed etching parameters, foils containing 7 × 10⁹ tracks/cm² exhibit much smaller pores than samples with 2 × 10⁸ tracks/cm². This effect is independent of the etching temperature and appears for irradiations with Pb ions as well as for Ca-ion tracks sensitized by UV exposure. Model calculations for different etching times and fluences show that the data for low track densities can be fitted quite well by describing the radial etching rate by the track etch rate changing into the bulk etch rate with a Gaussian-shaped transition.     

Bulk and track etch properties of CR-39 SSNTD etched in NaOH/ethanol

Recently, Matiullah et al. described the use of NaOH/ethanol as an etchant for the CR-39 detector, and have determined the corresponding bulk and track etch properties from the track diameter method. In the present work, the bulk and track etch properties of CR-39 in NaOH/ethanol were derived from direct measurements. The bulk etch rate has been found to increase with the molarity of NaOH/ethanol, reach a maximum at ∼2.5 N and start to drop beyond 3 N. The bulk etch rate also increases with stirring. These phenomena can be explained by the insulation of the detector from the etchant by the etched products. Regarding the track etch, we have found a surprising result that the lengths of (pre-etched) tracks are actually shortened when the tracks are etched in NaOH/ethanol. Generally speaking, the remaining track depths obtained with stirring are longer than those for no stirring. The shortening of the tracks can be explained by the insulation of the pre-etched track wall from the etchant with the etched products.     

径迹纳米孔高分子膜的制备和表征

载能重离子辐照高分子膜形成的离子潜径迹,经后续处理可制备出离子径迹纳米孔高分子膜。本文介绍了传统的离子径迹蚀刻法与最近发展的离子径迹紫外辐照方法制备径迹纳米孔高分子膜的过程及其纳米孔膜孔径的表征。离子径迹紫外辐照方法舍弃了传统离子径迹蚀刻法的化学蚀刻过程,所制备的径迹纳米孔高分子膜的孔密度高,孔道尺寸为纳米甚至亚纳米尺度,在海水淡化、离子分离等领域具有广阔的应用前景。     

载体孔结构对Pt/疏水陶瓷催化剂性能的影响

选用五种不同孔结构疏水陶瓷载体,采用浸渍-气相还原法制备用于水-氢交换的Pt/疏水陶瓷催化剂,经X射线衍射(XRD)、扫描电子显微镜(SEM)、H_2-程序升温还原法(H_2-TPR)及CO脉冲吸附等物性表征及催化剂催化活性(以催化交换活性kya表征)测试来考察载体孔结构对催化剂性能的影响。结果表明,随着平均孔径的降低,载体比表面积增加,催化剂铂粒子分散度提高,在30~70nm平均孔径范围内,催化剂活性随载体孔径的下降而得以提升;当平均孔径小于20nm时,反应气难以在较短时间内扩散至载体孔道内,相同时间内参与反应的活性位点总数较少,从而使得其催化活性有所下降。此外,载体孔隙率过高虽有助于提升比表面积,却使得载体结构较为疏松,在催化剂制备过程中载体孔结构易被破坏,对提升催化活性无利。平均孔径为37.5nm、载体比表面积为111.01m2/g、孔隙率为68.76%的载体可获得最优的催化效果,催化剂测试用量为4.5mL、氢气流速为4.23L/min时,其催化交换活性可达6.45s~(-1)。     

Study on Transmission of Near-infrared Light Through Polyester Films Modified by Nuclear Pores

Polyester membranes were irradiated by energetic ^32S ion beams from the HI-13 tandem accelerator, and then etched by NaOH solutions with different concentration, temperature, and etching time. These nuclear pore-modified membranes were studied on pore size, pore shape, and the transmission properties for near infrared light. Preliminary results show that the membranes produced with optimized pore density and etching conditions have higher transmission rate.     

Properties of poly(ethylene terephthalate) track membranes with a polymer layer obtained by plasma polymerization of pyrrole vapors

The structure and the charge transport properties of poly(ethylene terephthalate) track membrane modified by pyrrole plasma were studied. It was found that polymer deposition on the surface of a track membrane via plasma polymerization of pyrrole results in the creation of composite nanomembranes that, in the case of the formation of a semipermeable layer, possess asymmetric conductivity in electrolyte solutions - a rectification effect similar to that of a p-n junction in semiconductors. It is caused by presence in the membranes of two layers with different functional groups and also by the pore geometry. Such membranes can be used to create chemical and biochemical sensors.