共查询到19条相似文献,搜索用时 140 毫秒
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酸度对2-十八胺基甲酰基-8-羟基喹啉成膜性能的影响 总被引:1,自引:0,他引:1
两亲分子的成膜性能的研究主要集中在以羧基、磺酸基、磷酸基和第四铵盐等为亲水头基的化合物[1 ,2 ] ,而对亲水头基中兼有酸、碱性基团的两亲配体研究很少 ,本文报道了我们合成的一种新型两亲配体 2 -十八胺基甲酰基 - 8-羟基喹啉 (以下简写为 HL)在不同 p H的亚相溶液中单分子膜的形成。结果表明 ,HL在酸性亚相中不易成膜 ,而在碱性亚相中成膜性能较好 ,单分子膜由膨胀型向压缩型转变。并且讨论了亚相 p H对 HL单分子膜崩溃压的影响 ,以及 8-羟基喹啉头基在气 /液界面上的离解 -缔合情况。实 验 部 分一 .试剂与仪器2 -十八胺基甲… 相似文献
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提出普通表面活性剂(单链两亲分子)亲水头基相互作用诱导疏水尾链平行聚集形成双分子膜的新机制。设计和合成了系列单烷基取代乙二胺C~nH~2~n~+~1NHC~2H~4NH~2(n=8,12,14,16,18)。通过电镜形态,分散液凝胶/液晶相变和对应铸膜的二维双层结构,表明单链两亲分子头基相互作用和脂链引入刚性片断一样,两者形成的双分子膜具有类似的结构和性能;展示了各体系取代乙二胺双层结构和性能的密切联系。指出了广泛认同的单链两亲分子形成双分子膜必须引入刚性片断的单一成膜机制的片面性,为组装新一类功能头基表面活性剂双分子膜独辟蹊径。 相似文献
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研究了双头基两亲分子(Bolaamphiphile)N,N′-1,14-十四烷二酸酰-L-谷氨酸二乙酯(L-HDGE)和它的对映异构体D-HDGE在气液界面的组装;考察了HDGE分子的界面组装结构以及头部基团的手性,膜压和离子液体亚相对组装结构的影响.采用原子力显微镜(AFM)和傅里叶变换红外(FTIR)光谱对组装体的微观结构和组装机理进行了研究.结果表明,HDGE(L-HDGE或D-HDGE)在水亚相上可以组装得到平行排列,宽为50-120nm,高为1-5nm的纳米线.而将L-HDGE与D-HDGE混合组装时,只会得到疏松的薄膜结构.红外光谱表明HDGE分子的异手性相互作用强于同手性作用.在表面压继续上升时,纳米线可以发生一定聚集生成纳米带.亚相为一定浓度的离子液体时,会促进分子的聚集,在膜压的共同影响下,纳米带可以卷曲形成螺旋结构,螺旋的方向取决于头基的分子手性. 相似文献
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研究表面活性剂分子在水溶液中的聚集行为对模拟生物膜功能和研究分子间相互作用具有重要意义"'.用于形成囊泡双分子层的表面活性剂主要是类似天然磷脂的双烷基链两亲分子,单烷基链两亲分子在引人刚性基团时亦可形成双分子膜k'.含SChiff碱基两亲分子在水溶液中的聚集性质及间、尾链长度对SChiff碱基构象的影响已有报道"'.本文报道了这类分子的另一种重要成膜性质,即改变制备条件,可选择性地得到不同聚集结构和相变温度的双分子膜·实验中所用成膜分子为:CH。(CH。)。;OPh-N-CH-PhO(CH;)n;N"(CH。)。Br-(m-4;n-… 相似文献
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A series of membrane-spanning bolaamphiphiles (molecules with two hydrophilic end groups connected by a hydrophobic linker) were prepared by a modular synthetic method and evaluated for their abilities to affect the dynamics of a surrounding bilayer membrane. The goal was to determine if the bolaamphiphiles promote the translocation of phospholipids across vesicle membranes. The bolaamphiphiles were incorporated at low levels (up to 5 mol %) in vesicles composed of 1-palmitoyl-2-oleoyl-sn-glycero-3-phosphocholine (POPC). Inward translocation assays were performed using fluorescent, NBD-labeled phospholipid probes with phosphocholine (PC) or phosphoglycerol (PG) headgroups. The membrane-spanning bolaamphiphiles promote the translocation of both phospholipid probes in the order PG > PC, whereas shorter bolaamphiphiles (structures that must adopt a U-shape and keep both end groups in the same leaflet of the membrane), and regular amphiphiles with one hydrophilic end group, are inactive. These results are an exception to the rule-of-thumb that membrane-spanning bolaamphiphiles are inherently membrane-stabilizing molecules that inhibit all types of membrane transport. 相似文献
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Meister A Drescher S Garamus VM Karlsson G Graf G Dobner B Blume A 《Langmuir : the ACS journal of surfaces and colloids》2008,24(12):6238-6246
The temperature-dependent self-assembly and the mixing behavior of symmetrical single-chain bolaamphiphiles with different polymethylene chain lengths and different headgroup structures were investigated in water by differential scanning calorimetry (DSC), cryo transmission electron microscopy (cryo-TEM), and small angle neutron scattering (SANS). The even-numbered polymethylene-1,omega-bis(phosphocholines) (PC-C n-PC) are known to form nanofibers composed of stretched molecules with an all- trans alkyl chain conformation (Drescher, S.; Meister, A.; Blume, A.; Karlsson, G.; Almgren, M.; Dobner, B. Chem.Eur. J. 2007, 13, 5300-5307). The odd-numbered analogues were synthesized to study a possible even-odd effect of these bolaamphiphiles during their aggregation in water. In addition to these bolaamphiphiles with phosphocholine headgroups, a new series of polymethylene-1,omega-bis(phosphodimethylethanolamines) (Me2PE-Cn-Me2PE) with smaller headgroup sizes was synthesized. These bolaamphiphiles show an additional fiber-fiber transition when the alkyl chain length exceeds 26 carbon atoms. The mixing behavior of both types of bolaamphiphiles indicates that differences in the alkyl chain length up to six carbon atoms are tolerated within the fiber structure. The mixing of two Me2PE-Cn-Me2PE or PC-Cn-PC type bolaamphiphiles with different alkyl chain lengths offers the possibility to adjust the temperature, where the cross-linking of the fibers is disrupted and where the fibers break apart. As a consequence, temperature switchable hydrogels are obtained that can be fine-tuned for drug delivery applications. The comparison with dotriacontane-1,32-diyl-bis[2-(methylammonio)-ethylphosphate] (MePE-C32-MePE), a new bolaamphiphile with even smaller phosphomonomethylammonio headgroups, illustrates the importance of the headgroup size for the aggregation behavior. This bolaamphiphile self-assembles exclusively into lamellar structures, and this aggregate type persists in mixtures with the fiber forming Me2PE-C32-Me2PE. 相似文献
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Sun XL Biswas N Kai T Dai Z Dluhy RA Chaikof EL 《Langmuir : the ACS journal of surfaces and colloids》2006,22(3):1201-1208
Membrane-spanning phospholipid bolaamphiphiles either alone or as a constituent of a multicomponent lipid membrane may prove to be facile building blocks for generating robust bioactive membrane-mimetic assemblies. We have previously reported the synthesis of asymmetric dialkyl phospholipid bolaamphiphiles that contain ester linked phosphatidylcholine and amine functionalities at opposite chain ends. In this report, we describe the synthesis of phospholipid bolaamphiphiles that are conjugated to biotin via the terminal amine with or without a poly(ethylene oxide) spacer arm of varying chain length. The behavior of biotinylated bolaamphiphiles as a self-assembled monolayer at an air-water interface was characterized by epi-fluorescence microscopy and revealed that domain structure and pi-A isotherms were substantially influenced by linker type and size. Substrate bound assemblies were produced by Langmuir-Blodgett deposition onto planar substrates coated with an avidin derivatized polyelectrolyte multilayer. Significantly, external reflectance infrared spectroscopy confirmed the fabrication of bolaamphiphile thin films that display extended stability in vitro. 相似文献
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Organized assemblies in bolaamphiphile/oppositely charged conventional surfactant mixed systems 总被引:2,自引:0,他引:2
Five ionic bolaamphiphiles were synthesized and the aggregation behavior of bola single systems and bola/oppositely charged conventional surfactant mixed systems was studied. Small spherical vesicles were formed in all these mixed systems revealed by transmission electron microscopy (TEM). Variation of the structure of the hydrophobic chain of bolaamphiphiles has great influences on the vesicle formation ability. Vesicles were also found in the single system of a carboxylate bolaamphiphile, which was attributed to the hydrolysis of the bolaamphiphile. The results of FT-IR and X-ray diffraction (XRD) showed that bolaamphiphiles spanned through the vesicle membranes in these mixed systems. Super thermostability of the vesicles in this kind of mixed system was also investigated. 相似文献
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《Current Opinion in Colloid & Interface Science》2007,12(3):138-147
Over the past 2 years, various symmetrical and unsymmetrical bipolar amphiphiles (bolaamphiphiles) have been synthesized to study their self-organizing and packing properties alone as well as in mixtures with conventional amphiphiles. This review focuses on the lyotropic properties of these bolaamphiphiles and describes their in some cases quite unusual supramolecular self-assembling properties in aqueous media and at the air–water and liquid–solid interface. 相似文献
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Tobias Rudolph Naveen Kumar Allampally Gustavo Fernández Felix H. Schacher 《Chemistry (Weinheim an der Bergstrasse, Germany)》2014,20(43):13871-13875
We report an innovative template‐assisted synthetic protocol for the selective functionalization of terminal triple bonds in oligophenyleneethynylenes (OPE) by pre‐organization in aqueous solution. By this approach, three new OPE‐based bolaamphiphiles substituted with hydrophilic poly(2‐ethyl‐2‐oxazoline) (PEtOx) chains of different length have been synthesized. The chain length was observed to strongly influence the aqueous supramolecular polymerization: bolaamphiphiles with longer hydrophilic chains aggregate into spherical nanoparticles in a stepwise fashion, whereas 2D anisotropic platelets are formed cooperatively if shorter PEtOx chains are used. Our results demonstrate that hydrophobic interactions can be strong enough to trigger cooperative effects in aqueous self‐assembly processes. 相似文献
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Song B Liu G Xu R Yin S Wang Z Zhang X 《Langmuir : the ACS journal of surfaces and colloids》2008,24(8):3734-3739
This article discusses the relationship between the molecular structure of bolaamphiphiles bearing mesogenic groups and their interfacial self-organized morphology. On the basis of the molecular structures of bolaamphiphiles, we designed and synthesized a series of molecules with different hydrophobic alkyl chain lengths, hydrophilic headgroups, mesogenic groups, and connectors between the alkyl chains and the mesogenic group. Through investigating their interfacial self-organization behavior, some experiential rules are summarized: (1) An appropriate alkyl chain length is necessary to form stable surface micelles; (2) different categories of headgroups have a great effect on the interfacial self-organized morphology; (3) different types of mesogenic groups have little effect on the structure of the interfacial assembly when it is changed from biphenyl to azobenzene or stilbene; (4) the orientation of the ester linker between the mesogenic group and alkyl chain can greatly influence the interfacial self-organization behavior. It is anticipated that this line of research may be helpful for the molecular engineering of bolaamphiphiles to form tailor-made morphologies. 相似文献
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Roussel M Lognoné V Plusquellec D Benvegnu T 《Chemical communications (Cambridge, England)》2006,(34):3622-3624
New dissymmetrical neutral-cationic or anionic-cationic alpha,omega-diamido bolaamphiphiles have been synthesized in which the polar headgroups are derived from alginate and glycine betaine and which exhibit monolayer lipid membrane vesicles, large lamellae and rods. 相似文献
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Kai T Sun XL Faucher KM Apkarian RP Chaikof EL 《The Journal of organic chemistry》2005,70(7):2606-2615
[structure: see text] A synthetic route was devised for the generation of asymmetric lipid bolaamphiphiles through the sequential esterification of an alkyldioic acid, bearing distinct terminal protecting groups, with propanylamine and lyso-phosphatidylcholine headgroups. Bolaamphiphile self-assembly was investigated in solvent mixes of varying polarity by nuclear magnetic resonance (NMR) and Fourier transform-infrared (FT-IR) spectroscopy, as well as in water by cryo-high-resolution scanning electron microscopy (cryo-HRSEM). We anticipate that asymmetric lipid bolaamphiphiles will provide facile building blocks for engineering a variety of unique membrane-mimetic structures. 相似文献