共查询到20条相似文献,搜索用时 125 毫秒
1.
发展简单、高效、可控的方法来制备中空介孔微球是介孔材料领域的研究热点.本工作结合嵌段共聚物的三维受限自组装(3D-CSA)和自模板碳化策略,建立了一种构筑中空介孔微球的新方法 .首先,采用乳液-溶剂挥发法实现嵌段共聚物与全氟辛烷(PFO)在3D受限空间的分级组装,获得了核-壳结构微球,其中壳层由微相分离的嵌段共聚物构成.然后,在壳层的连续相选择性地复合氧化硅,既实现了无机框架的负载,又实现了对连续相聚合物链选择性交联.对复合微球进行煅烧处理后,实现了壳层连续相聚合物的选择性碳化,获得了中空介孔氧化硅/碳复合微球.本研究系统地阐述了核-壳型分级结构微球的形成机理和必备条件,研究了氧化硅前驱体添加量和嵌段共聚物分子量对中空介孔氧化硅/碳复合微球形貌的影响,为制备中空介孔微球材料提供了一种简便、可控的方法. 相似文献
2.
3.
4.
5.
采用耗散粒子动力学方法,研究了两亲性嵌段共聚物和双疏性嵌段共聚物共混体系的自组装行为,探讨了双疏性嵌段共聚物的浓度以及双疏性嵌段共聚物的嵌段体积分数对聚集体结构的影响.结果表明,随着双疏性嵌段共聚物浓度的增加,聚集体发生自囊泡到棒状胶束再到同心圆多舱胶束的转变,且当浓度较高时,同心圆多舱胶束的同心圆层数量与浓度密切相关.当双疏性嵌段共聚物中的嵌段体积分数降低时,球形胶束由同心圆结构转变为非同心圆结构.此外,利用Minkowski泛函方法表征了多舱胶束的形成过程,发现这是一个先形成大尺度球形结构、再形成小尺度内核结构的分级组装过程. 相似文献
6.
7.
8.
采用Monte Carlo模拟方法研究了在平行板受限条件下A_(15)B_5非对称两嵌段共聚物与纳米粒子复合物的自组装行为,其中平行板对多组分嵌段A具有吸引相互作用.模拟结果表明,纳米粒子在两嵌段共聚物/纳米粒子复合物中的体积分数、嵌段共聚物不同嵌段与纳米粒子间的相互作用均对体系在平行板受限条件下的形貌结构及纳米粒子在体系中的分布有重要影响.当平行板间距一定时,未添加纳米粒子的A_(15)B_5非对称两嵌段共聚物中的A嵌段被吸附在平行板上形成层状相,而B嵌段则在平行板中形成六角堆积穿孔层状结构.加入与A嵌段不相容而与B嵌段相容的纳米粒子后,增加了纳米粒子与B嵌段的相容性,有利于保持B嵌段所形成的穿孔结构及孔洞尺寸,同时纳米粒子能够均匀地分散在B相区中.当引入的纳米粒子与A和B两嵌段均不相容时,降低纳米粒子与嵌段共聚物的不相容性同样有利于维持体系的穿孔结构.当纳米粒子与AB两嵌段共聚物间的排斥作用微弱时,即使含量较高,纳米粒子也不聚集,并且均匀分布在A相区与B相区的交界处. 相似文献
9.
采用两步溶液聚合方法合成了一系列聚二甲基硅氧烷(PDMS)-4,4′-二苯基甲烷二异氰酸酯(MDI)-聚乙二醇(PEG)多嵌段共聚物.利用轻敲模式原子力显微镜(AFM)观察了嵌段共聚物的表明形貌,研究了退火、共聚物组成以及PEG分子量和不同的官能团对涂层表面微相分离行为的影响,同时对微相分离行为的形成机理也作了相应的探讨.研究表明,该嵌段共聚物即使在PDMS含量大于50wt%时,涂层表面仍呈现出规整有序的纳米级相分离结构,其中疏水相和亲水相分别由PDMS链段和MDI-PEG组分构成. 相似文献
10.
11.
Multipod structures of lamellae‐forming diblock copolymers in three‐dimensional confinement spaces: Experimental observation and computer simulation
下载免费PDF全文
![点击此处可从《Journal of Polymer Science.Polymer Physics》网站下载免费的PDF全文](/ch/ext_images/free.gif)
Takeshi Higuchi Marco Pinna Andrei V. Zvelindovsky Hiroshi Jinnai Hiroshi Yabu 《Journal of Polymer Science.Polymer Physics》2016,54(17):1702-1709
The three‐dimensional (3D) confinement effect on the microphase‐separated structure of a diblock copolymer was investigated both experimentally and computationally. Block copolymer nanoparticles were prepared by adding a poor solvent into a block copolymer solution and subsequently evaporating the good solvent. The 3D structures of the nanoparticles were quantitatively determined with transmission electron microtomography (TEMT). TEMT observations revealed that various complex structures, including tennis‐ball, mushroom‐like, and multipod structures, were formed in the 3D confinement. Detailed structural analysis, showed that one block of the diblock copolymer slightly prefers to segregate into the particle surface compared with the other block. The observed structures were further elaborated using cell dynamics computer simulation. © 2016 Wiley Periodicals, Inc. J. Polym. Sci., Part B: Polym. Phys. 2016 , 54, 1702–1709 相似文献
12.
13.
The phase behaviors of comblike block copolymer A(m+1)B(m)/homopolymer A mixtures are studied by using the random phase approximation method and real-space self-consistent field theory. From the spinodals of macrophase separation and microphase separation, we can find that the number of graft and the length of the homopolymer A have great effects on the phase behavior of the blend. For a given composition of comblike block copolymer, increasing the number of graft does not change the macrophase separation spinodal curve but decreases the microphase separation region. The addition of a small quantity of long-chain homopolymer A increases the microphase separation of comblike block copolymer/homopolymer A mixture. However, the addition of short-chain homopolymer A will decrease the phase separation region of comblike block copolymer/homopolymer A mixture. It is also found that the microstructure formed by diblock copolymer is easier to be swelled by homopolymer than that formed by comblike block copolymer. This can be attributed to the architecture difference between the comblike block copolymer and linear block copolymer. 相似文献
14.
15.
16.
聚丁二烯-b-甲基丙烯酸甲酯共聚物的聚集态研究周庆业,张邦华,宋谋道,何炳林(南开大学高分子化学研究所,天津,300071)关键词共聚物,相分离,聚集态结构嵌段共聚物按其组成、合成及成型条件的不同可形成丰富的相结构[1],其动态力学性能,如在损耗模量... 相似文献
17.
Sonja Krause 《Journal of Polymer Science.Polymer Physics》1985,23(1):129-142
A simple theoretical treatment of microphase separation in block copolymers [S. Krause, Macromolecules, 3 , 84 (1970)] has been extended to the case in which individual molecules of the block copolymer may dissolve in one or the other of the microphases. When the free energy driving force for microphase separation is near zero, the minimum free energy state of the system has a relatively high concentration of block copolymer molecules dissolved in one or in both of the microphases, depending partly on the percent composition of the block copolymer. The theoretical predictions are compared with experimental data in the literature. 相似文献
18.
Hiroshi Yabu Tatsuya Jinno Kazutaka Koike Takeshi Higuchi Masatsugu Shimomura 《Journal of Polymer Science.Polymer Physics》2011,49(24):1717-1722
In this study, metal‐polymer particles with microphase‐separated structures were prepared by self‐organized precipitation, where a good solvent is evaporated from a solution that also contains block copolymer, Au NPs, and a poor solvent. Control of the microphase‐separated structure in composite particles consisting of Au NPs and block copolymer was accomplished by changing the Au NP size, the mix ratio, and the copolymerization ratio of the block copolymer. The morphology of the inner structures was changed from a lamellar phase to a spherical phase by increasing the Au NP concentration. © 2011 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys, 2011 相似文献
19.
O. V. Slisenko O. P. Grigor’eva O. N. Starostenko D. I. Sukhorukov E. V. Lebedev 《Polymer Science Series A》2006,48(8):809-820
New film-forming polymer composites based on the semicrystalline polyurethane and the styreneacrylic acid block copolymer have been synthesized. The effect of hydrogen bonds on the phase structure and properties of the composites has been studied by dynamic MTA, DSC, thermogravimetry, and IR spectroscopy. Formation of the network of intermolecular hydrogen bonds between urethane groups of polyurethane and carboxyl groups of block copolymer components leads to a decrease in the microphase separation of the composites under study and improves their thermooxidative stability. 相似文献
20.
采用耗散粒子动力学(DPD)方法研究了嵌段共聚物在纳米微滴中的相分离行为.模拟是将共聚物纳米微滴置于溶剂环境中进行自发相分离,从而形成一些图案化结构.由于是受限体系,所形成的结构和在溶液或熔融体中形成的相分离结构有所差异,这些结构的形成与亲/疏溶剂嵌段比例(RH/T)有关系.随着亲/疏溶剂嵌段比例的增加,依次形成了枣糕球体、排球状相、多层囊泡(洋葱相)、笼状相、纳米杆状相和分散胶束等结构.我们对洋葱相的形成过程进行了详细的描述.溶剂粒子的集群属性有助于更加深入地了解洋葱相的结构衍化.采用密度曲线分析了洋葱相的结构.在较高的亲/疏溶剂嵌段的比例条件下,嵌段共聚物主要表现为亲溶剂性,通过吸收大量的溶剂溶胀形成疏松结构或瓦解形成分散的胶束悬浮在溶剂中.本文模拟结果与理论或实验结果基本吻合. 相似文献