Creation of Faceted Polyhedral Microgels from Compressed Emulsions

Compressed monodisperse emulsions in confined space exhibit highly ordered structures. The influence of the volume fraction and the confinement geometry on the organized structures is investigated and the mechanism by which structural transition occurs is studied. Based on the understanding of ordering behavior of compressed emulsions, a simple and high‐throughput method to fabricate monodisperse polyhedral microgels using the emulsions as the template is developed. By controlling the geometry of the confined spaces, a variety of shapes such as hexagonal prism, Fejes Toth honeycomb prism, truncated octahedron, pyritohedron, and truncated hexagonal trapezohedron are implemented. Moreover, the edge sharpness of each shape is controllable by adjusting the drop volume fraction. This design principle can be readily extended to other shapes and materials, and therefore provides a useful means to create polyhedral microparticles for both fundamental study and practical applications.     

Liquid‐Filling Polydimethylsiloxane Composites with Enhanced Triboelectric Performance for Flexible Nanogenerators

Material functionalization of triboelectric nanogenerators (TENG) plays an important role in TENG's electric performance for sustainable energy harvesting. In this work, a method for improving polydimethylsiloxane (PDMS) composites triboelectric performance has been proposed, via filling high dielectric constant liquid (instead of solids) into PDMS matrix. The improvement is attributed to the high dielectric constant liquid in PDMS matrix that reduced the effective thickness of PDMS and increased the dielectric constant of PDMS composite synchronously. At 50% filling ratio (PDMS‐HD50), the triboelectric performance exhibits an enhancement of 4.5‐fold in output voltage and 3.9‐fold in output current as compared to pure PDMS. The results, besides higher transparency, are superior to the results from traditional solid dielectric constant doping materials like BaTiO₃ nanoparticle in PDMS. This work has proved potentials of dielectric liquid filling materials in fabricating TENGs and could be a guidance for exploring new liquid filling materials.     

κ-卡拉胶影响大豆分离蛋白乳浊液稳定性的研究

研究了卡拉胶对大豆分离蛋白乳浊液粒度分布、乳析率和离心沉淀率的影响,在此基础上分析了静置过程中乳浊液粒径与乳析率、离心沉淀率之间相关性,结果表明:乳浊液粒径随卡拉胶浓度由小到大依次为0.03%<空白样<0.06%<0.09%;而体系的表观粘度随卡拉胶浓度的增大而升高;静置过程中乳浊液顶部粒径d3,2与乳析率有较好的相关性;乳浊液底部d3,2与离心沉淀率有很好的相关性。进一步分析了其可能的作用机理:卡拉胶低浓度时,卡拉胶分子被吸附到液滴的蛋白质正电荷区域,增加了液滴间的静电排斥,从而增加了体系的絮凝稳定性;随着卡拉胶浓度增大,卡拉胶会引起体系排斥絮凝。     

水/甲醇和柴油乳化液的黏度特性实验研究

为研究水/甲醇和柴油乳化液的流变特性与黏度,实验采用了Span80和Tween60配制的3种复合乳化剂Y01、Y02和Y03,它们的HLB值分别为5.36、4.83和4.51.Y03为牛顿流体,动力黏度约为1.5Pa·s.在高剪切速率下,Y01与Y02近似为牛顿流体,动力黏度分别为Y03的88%和92%.乳化液中水相(水与甲醇)总量为10%～50%,乳化剂含量0.8%～8%,动力黏度约在0.003Pa·s到0.02Pa·s之间,为牛顿流体.实验结果表明,如果其它条件不变,乳化液黏度变化规律为:乳化剂HLB值的不同对乳化剂黏度有较大影响;乳化剂含量对乳化液黏度有显著影响,特别当水相含量高于40%时,影响特别显著;提高水相含量(不超过50%),乳化液黏度上升,当水相含量超过40%时,乳化剂含量低于2%和高于4%对乳化液的黏度影响规律明显不同;水相中水与甲醇的比例变化时,对乳化液的黏度影响比较复杂.用乳化液相间界面特征和HLB特征可以从理论上解释上述现象.     

介质弹性对多重乳液分散度的影响

多重乳液的单分散性是与粒径相关的一些重要性质如乳液稳定性、乳化剂界面分配等研究工作的基础.在保证连续相与分散相的粘度比∈(0.1,1)条件下,分别以聚丙烯酰胺及甘油为连续相,以不同内相体积w1/o一级乳液为分散相,在相应流变性质研究的基础上,研究了介质的弹性对多重乳液分散度的影响,制备了分散度20%左右的拟单分散多重乳液体系.研究表明,连续相的弹性是制备拟单分散多重乳液的必要条件,分散相的弹性有利于单分散多重乳液的制备.完善了前人的相关研究结果.     

Multifunctional phase change microcapsules based on graphene oxide Pickering emulsion for photothermal energy conversion and superhydrophobicity

In order to enlarge the applications of microencapsulated phase change materials (microPCMs), the novel stearic acid (SA)@graphene oxide (GO)/melamine-formaldehyde (MF) multifunctional superhydrophobic microPCMs were prepared with the method of condensation polymerization. We have made a systematical study of the effects of GO content on the SA@GO/MF microPCMs. The morphology and chemical composition characterizations showed the successful fabrication of microcapsules. The differential scanning calorimeter (DSC) identified that microPCMs could store latent heat energy. According to the contact angles (CA) measurement, the microPCMs displayed the water contact angle of 160.2°, which possessed the superhydrophobic property. Moreover, the self-cleaning property of SA@GO/MF microPCMs was demonstrated by designing self-cleaning experiment. The simulated irradiation experiment showed the good photothermal conversion performance of microPCMs. Owing to photothermal energy conversion performance and superhydrophobicity, multifunctional phase change microcapsules could have vital potentials in energy conversion and self-cleaning.     

The effect of additives on the treatment of oil-in-water emulsions by vacuum evaporation

A simple batch vacuum evaporation process for the treatment of several oil-in-water (O/W) emulsions is reported. The experiments were carried out with waste emulsions from an industrial copper rolling process and with model emulsions prepared in the laboratory. No detailed information on the formulation of the industrial waste O/W emulsions was available. Several model emulsions were formulated using the same base oil (an 85–15% (w/w) mixture of a synthetic poly-α-olefin and a trimethylol propane trioleate ester, respectively) and one of the three following surfactants: Brij-76 (polyethylene glycol octadecyl ether, non-ionic), CTAB (hexadecyltrimethyl ammonium bromide, cationic), and Oleth-10 (glycolic acid ethoxylate oleyl ether, anionic). Experimental results show a strong influence of operating conditions, such as pressure or bath temperature, on the evaporation performance. As a general trend, the higher the values of these parameters, the higher the pollutant content in the obtained aqueous effluent. The presence of surfactants increase the evaporation rate, especially at low operating vacuum pressures, the solubility of oil molecules in water and the evaporation temperature of model O/W emulsions. Furthermore, COD reductions higher than 99.5% for the treated waste O/W emulsions were achieved.     

Pickering乳液在油基钻井液中的应用

Pickering乳液以其较高的聚并稳定性、多样性、可调控性、低成本、低毒性和生物兼容性等优势,广泛应用于生物医学、食品和化妆品等领域。近年来,Pickering乳液在石油行业的应用备受关注。分析了Pickering乳液的稳定机理与其相较于传统乳液的优势;探究了影响Pickering乳液稳定性的诸多因素及调控方式;最后综述了近年来国内外Pickering乳液在钻井和驱油方面的应用,并对Pickering乳液在石油行业中的发展前景进行了展望。