聚对苯撑导电膜的合成及其电化学性能

本文采用电化学循环伏安法制备得到聚对苯撑(PPP)导电膜,通过FTIR、XPS、四探针、交流阻抗(EIS)等手段对其结构及电性能进行表征,并考察了电化学条件与聚对苯撑膜的电化学性能之间的关系。研究表明,合成的PPP膜的平均聚合度为10.8,电导率在2.0～5.0S/cm范围内。于0.6V恒电位10min后,PPP膜的掺杂量可达25%。在0～1.0V电位范围内,PPP膜具有良好的电化学氧化还原性。交流阻抗的进一步研究表明,随着外加电位的正移,聚对苯撑膜的掺杂程度提高,膜的Rct由0V的329.7Ωcm2降低至0.6V的15.60Ωcm2,Cdl由0V的1.164μFcm-2增至0.6V的172.7μF cm-2。膜反应电阻和双电层电容的变化表明PPP膜在掺杂过程中形成开放结构,便于溶液中的离子与溶剂交换。     

Electrochemical preparation and characterisation of Poly(Luminol-Aniline) films

Electrochemical polymerisation of luminol (Lum) with aniline (Ani) is carried out potentiodynamically from acidic medium with different monomers concentration ratios. Aniline units incorporation in the polymer structure is observable in the current density/potential profiles of the polymerisation and characterisation, in acidic medium, by the development of two polyaniline (PAni) like redox switching processes with increasing aniline concentration. Poly(Luminol-Aniline) (P(Lum-Ani)) films characterised in acidic medium show electroactive and stable behaviour, in which the redox process ascribed as polyluminol (PLum) type is overlaid with that of PAni displaying pH sensitivity. Unlike PAni films, the P(Lum-Ani) polymer is electroactive and stable in basic medium and a single redox switching process is observed; its redox charge is enhanced with the increase of aniline concentration in the polymerisation solution.     

Poly(aniline) nanowires in sol-gel coated ITO: a pH-responsive substrate for planar supported lipid bilayers

Facilitated ion transport across an artificial lipid bilayer coupled to a solid substrate is a function common to several types of bioelectronic devices based on supported membranes, including biomimetic fuel cells and ion channel biosensors. Described here is fabrication of a pH-sensitive transducer composed of a porous sol-gel layer derivatized with poly(aniline) (PANI) nanowires grown from an underlying planar indium-tin oxide (ITO) electrode. The upper sol-gel surface is hydrophilic, smooth, and compatible with deposition of a planar supported lipid bilayer (PSLB) formed via vesicle fusion. Conducting tip AFM was used to show that the PANI wires are connected to the ITO, which convert this electrode into a potentiometric pH sensor. The response to changes in the pH of the buffer contacting the PANI nanowire/sol-gel/ITO electrode is blocked by the very low ion permeability of the overlying fluid PSLB. The feasibility of using this assembly to monitor facilitated proton transport across the PSLB was demonstrated by doping the membrane with lipophilic ionophores that respond to a transmembrane pH gradient, which produced an apparent proton permeability several orders of magnitude greater than values measured for undoped lipid bilayers.     

Poly(N-methyl aniline) thin films on copper: Synthesis, characterization and corrosion protection

Poly(N-methyl aniline) (PNMA) coatings were synthesized on copper by electrochemical polymerization of N-methyl aniline in aqueous oxalic acid solution by using cyclic voltammetry. The optimum electrodeposition conditions (e.g. upper potential limit, scan rate and cycle number) were determined in order to obtain PNMA coatings to have the best corrosion performance. PNMA coatings were characterized by cyclic voltammetry, Fourier Transform Infrared-Attenuated Total Reflectance spectroscopy and scanning electron microscopy. Redox parameters found after electrochemical tests indicate a thin film character and diffusion controlled electroactive behavior of PNMA. Corrosion test results revealed that PNMA coating appears to enhance protection of copper in 0.1 M H₂SO₄ solution.     

聚乙烯醇-魔芋葡甘聚糖包装膜透光率与雾度

目的研究影响聚乙烯醇-魔芋葡甘聚糖包装膜透光率和雾度的因素。方法以甘油、山梨醇为复配增塑剂,将纯化过的魔芋精粉和聚乙烯醇按一定质量比混合后水浴恒温共混,流延干燥制备包装膜,研究共混温度、共混时间、基料配比、复配增塑剂配比对包装膜透光率和雾度的影响。结果魔芋精粉和聚乙烯醇按质量比为1∶10混合,在水浴温度80℃下恒温共混3 h,加入质量分数为10%的复配增塑剂,复配增塑剂中山梨醇和甘油的质量比控制在1∶2~1∶3时制备的包装膜透光率和雾度达到最佳。结论各因素对包装膜的透光率和雾度有较大影响,原因是它们能促使魔芋葡甘聚糖分子和聚乙烯醇分子形成强烈的协同作用。     

Alloy Nanocatalysts for the Electrochemical Oxygen Reduction (ORR) and the Direct Electrochemical Carbon Dioxide Reduction Reaction (CO2RR)

In the face of the global energy challenge and progressing global climate change, renewable energy systems and components, such as fuel cells and electrolyzers, which close the energetic oxygen and carbon cycles, have become a technology development priority. The electrochemical oxygen reduction reaction (ORR) and the direct electrochemical carbon dioxide reduction reaction (CO₂RR) are important electrocatalytic processes that proceed at gas diffusion electrodes of hydrogen fuel cells and CO₂ electrolyzers, respectively. However, their low catalytic activity (voltage efficiency), limited long‐term stability, and moderate product selectivity (related to their Faradaic efficiency) have remained challenges. To address these, suitable catalysts are required. This review addresses the current state of research on Pt‐based and Cu‐based nanoalloy electrocatalysts for ORR and CO₂RR, respectively, and critically compares and contrasts key performance parameters such as activity, selectivity, and durability. In particular, Pt nanoparticles alloyed with transition metals, post‐transition metals and lanthanides, are discussed, as well as the material characterization and their performance for the ORR. Then, bimetallic Cu nanoalloy catalysts are reviewed and organized according to their main reaction product generated by the second metal. This review concludes with a perspective on nanoalloy catalysts for the ORR and the CO₂RR, and proposes future research directions.     

PLLA/PBLG嵌段共聚物的合成及其结构表征

以L-丙交酯(LLA)为原料,在催化剂辛酸锡酯Sn(Oct)2的作用下,利用聚(γ-谷氨酸苄酯)的活性端氨基引发LLA进行开环聚合,合成了聚L-丙交酯 (PLLA)与聚(γ-谷氨酸苄酯)(PBLG)的共聚物,对反应条件的各项因素进行了讨论,确定了最佳反应条件是:m(催化剂):m(PBLG)=1:1;反应温度120℃;反应时间6h.并利用红外、核磁和凝胶渗透色谱方法对产物的结构进行表征.结果表明,所制备的共聚物为PLLA/PBLG/PLLA三嵌段共聚物.     

以聚苯乙烯磺酸钠接枝聚乙二醇为模板的聚3,4-二氧乙烯噻吩水分散体的制备及性能

以苯乙烯磺酸钠(SSNa)和烯丙基聚乙二醇(APEG)为原料,制备了不同结构的聚苯乙烯磺酸钠接枝聚乙二醇(P(SS-APEG))共聚物,并以此为模板制备了聚3,4-二氧乙烯噻吩∶聚(苯乙烯磺酸钠-烯丙基聚乙二醇)(PEDOT∶P(SS-APEG))水分散体;研究了聚乙二醇(PEG)链段长度对PEDOT∶P(SS-APEG)结构与性能的影响。结果表明,通过自由基共聚,成功制备了聚苯乙烯磺酸钠接枝聚乙二醇(P(SS-APEG))共聚物。以P(SS-APEG)为模板时,EDOT的聚合速率加快,分散体粒径随APEG相对分子质量的增加而增大,水分散体表面张力减小。PEDOT薄膜的方块电阻明显降低,且APEG的相对分子质量越小,薄膜的方块电阻越低,导电性越好。当APEG的相对分子质量为700,n(SSNa)∶n(APEG)=32∶1,m(EDOT)∶m(P(SS-APEG))=1∶3时,PEDOT∶P(SS-APEG)薄膜的方块电阻较PEDOT∶PSS(m(EDOT)∶m(PSS)=1∶3)薄膜下降了3倍。     

Electrochemical Characteristics of LaNi_(4.5)Al_(0.5) Alloy Used as Anodic Catalyst in a Direct Borohydride Fuel Cell

Fuel cells using borohydride as the fuel have received much attention because of high energy density and theoretical working potential.In this work,LaNi4.5Al0.5 hydrogen storage alloy used as the anodic material has been investigated.It was found that the increasing operation temperature was helpful to the open-circuit potential,the discharge potential and the power density,but showed a negative effect on the utilization of the fuel due to the accelerated hydrogen evolution.The high KOH concentration was favorable for high-rate discharge capability.The adsorption and transformation of hydrogen on LaNi4.5Al0.5 alloy electrode has been observed,but its contribution to the discharge capability during a high-rate discharge was small.     

非晶态MmNi5.20合金薄膜的制备及析氢反应电催化性能的研究

用离子束溅射法制备非晶态ＭｍＮｉ＿（５．２０）合金薄膜。该非晶态合金薄膜在３０ｗｔ％ＫＯＨ，７０℃作析氢反应电极。实验结果表明，该电极不但具有良好的析氢电催化活性和电化学稳定性，而且具有很好的抗氢脆和抗粉化能力。交流阻抗分析表明，非晶态ＭｍＮｉ＿（５．２０）合金电极析氢反应过程主要由电化学反应步骤控制。     

Electrochemical performances and thermal properties of electrospun Poly(phthalazinone ether sulfone ketone) membrane for lithium-ion battery

A novel Poly(phthalazinone ether sulfone ketone) (PPESK) membrane for lithium-ion battery was prepared using electrospinning technique. The morphology, electrochemical performances and thermal properties of electrospun PPESK fabrics were investigated. Results indicate that electrospun PPESK fabrics have high porosity of 92% and high electrolyte uptake of 1210%, which lead to their high ionic conductivity of 3.79 × 10^− 3 S·cm^− 1 at 25 °C. The cell assembled with PPESK fabrics displays better electrochemical stability and higher cycling discharge capacity than that assembled with PVDF fabrics. Moreover, electrospun PPESK fabrics exhibit excellent thermal dimensional stability. When PPESK fabrics are treated in oven at 220 °C for 1 h, the shape of membrane is unchanged. Electrospun PPESK fabrics have possible applications for high performance lithium-ion battery.     

细乳液法制备有机硅氧烷改性苯丙乳液

采用细乳液法制备γ-甲基丙烯酰氧基正丙基三甲氧基硅烷(MPS)改性苯丙乳液。研究了引发剂、pH值、MPS的用量等对乳胶膜凝胶含量、溶胀比及动态力学性能的影响。溶胀实验表明,乳胶粒子和乳胶膜凝胶含量及溶胀比主要受体系的pH值影响比较大。动态力学分析表明,在中性条件下使用过硫酸钾(KPS)引发剂得到的乳胶膜的储存模量要高于偶氮二异丁腈(AIBN)乳胶膜的储存模量;增加MPS的用量以及对乳胶膜进行酸化处理或热处理可以提高乳胶膜的储存模量。     

一种具有网状结构聚苯乙烯聚氨酯的合成及表征

将聚对羟甲基苯乙烯用异佛尔酮二异氰酸酯(IPDI)交联,制备了一种具有网状结构的聚苯乙烯聚氨酯,并用核磁共振法(1H-NMR),红外分析法(FT-IR)对其结构作了表征。用差示扫描量热法(DSC),热失重法(TGA/DTG)测定了其热分解性质,发现聚合物具有良好的热稳定性,增大IPDI的含量,聚合物的热分解温度提高。DSC和扫描电镜(SEM)测试表明,增大IPDI的含量也使聚合物微相分离程度提高。对聚合物进行紫外光照射和微生物催化水解,发现聚合物具有光降解和生物降解性。     

纳米纤维素晶须对聚乳酸薄膜的结构和力学及阻隔性能的影响

为了改善聚乳酸(PLA)薄膜的韧性和阻隔性能,文中利用流延法制备了不同配比的PLA/纳米纤维素晶须(NCW)复合薄膜,并对其结构、热性能、力学及阻隔性能进行了研究。研究发现,NCW加入后,在PLA基体中分散不均,添加3-氨丙基三乙氧基硅烷(APTS)为界面改性剂后,其在基体中的分散性明显改善;NCW的加入会提高薄膜的玻璃化转变温度、结晶温度和熔融温度,对PLA的结晶有促进作用,并能明显提高薄膜的热稳定性;NCW加入后,会导致薄膜的拉伸强度和模量的降低,但当APTS添加后,薄膜的强度和模量有所改善,薄膜的断裂伸长率会随着NCW含量的增加而明显增大;另外,NCW的添加有助于薄膜阻隔性能的提高。     

聚(3-羟基丁酸酯-co-4-羟基丁酸酯)/酶解木质素共混材料的制备及性能

双螺杆熔融共混制备了全生物降解的聚(3-羟基丁酸酯-co-4-羟基丁酸酯)(P3HB4HB)/纤维素酶解木质素(CEL)共混物,分别用热重分析、拉伸弯曲试验、冲击试验、扫描电镜(SEM)考察了CEL含量对共混物热学、力学性能及微观形貌的影响。研究发现,CEL的加入增强了材料的热稳定性,也提高了材料的模量,但断裂伸长率、拉伸强度、弯曲强度和冲击强度平缓降低,当CEL的质量分数为20%CEL,拉伸、弯曲、冲击三种强度的保持率都大于93%;SEM显示,P3HB4HB和CEL相容很好。CEL填充P3HB4HB不仅能降低材料成本,还能对材料的热学、力学性能保持较好或起改善作用,CEL最宜添加的质量分数为20%。