Articles de revues : « Electrostatic assemblies »

1

Wu, David, David Chandler et Berend Smit. « Electrostatic analogy for surfactant assemblies ». Journal of Physical Chemistry 96, n^o 10 (mai 1992) : 4077–83. http://dx.doi.org/10.1021/j100189a030.

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White, Rod, et Stephen Bolser. « Acoustic Transparency of Electrostatic Loudspeaker Assemblies ». Journal of the Audio Engineering Society 65, n^o 6 (27 juin 2017) : 497–506. http://dx.doi.org/10.17743/jaes.2017.0015.

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Martin, Lisal, Sindelka Karel, Sueha Lucie, Limpouchova Zuzana et Prochazka Karel. « Dissipative Particle Dynamics Simulations of Polyelectrolyte Self-Assemblies. Methods with Explicit Electrostatics1, "Высокомолекулярные соединения. Серия С" ». Высокомолекулярные соединения С, n^o 1 (2017) : 82–107. http://dx.doi.org/10.7868/s2308114717010101.

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Abstract - This feature article is addressed to a broad community of polymer scientists, both theoreticians and experimentalists. We present several examples of our dissipative particle dynamics (DPD) simulations of self- and co-assembling polyelectrolyte systems to illustrate the power of DPD. In the first part, we briefly outline basic principles of DPD. Special emphasis is placed on the incorporation of explicit electrostatic forces into DPD, on their calibration with respect to the soft repulsion forces and on the use of DPD for studying the self-assembly of electrically charged polymer systems. At present, the method with explicit electrostatics is being used in a number of studies of the behavior of single polyelectrolyte chains, their interaction with other components of the system, etc. However, in DPD studies of self-assembly, which require high numbers of chains, only a few research groups use explicit electrostatics. Most studies of polyelectrolyte self-assembly are based on the “implicit solvent ionic strength” approach, which completely ignores the long-range character of electrostatic interactions, because their evaluation complicates and considerably slows down the DPD simulation runs. We aim at the analysis of the impact of explicit electrostatics on simulation results.

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Chen, Charlotte H., Liam C. Palmer et Samuel I. Stupp. « Self-sorting in supramolecular assemblies ». Soft Matter 17, n^o 14 (2021) : 3902–12. http://dx.doi.org/10.1039/d1sm00113b.

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Two minority fluorescent constituents of a multicomponent supramolecular system undergo self-sorting, mediated by their electrostatic interactions with a third non-fluorescent constituent that comprises 99 mol% of the system.

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Domínguez, Elena, Guillaume Suárez et Arántzazu Narváez. « Electrostatic Assemblies for Bioelectrocatalytic and Bioelectronic Applications ». Electroanalysis 18, n^o 19-20 (octobre 2006) : 1871–78. http://dx.doi.org/10.1002/elan.200603625.

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Zika, Alexander, Sarah Bernhardt et Franziska Gröhn. « Photoresponsive Photoacid-Macroion Nano-Assemblies ». Polymers 12, n^o 8 (5 août 2020) : 1746. http://dx.doi.org/10.3390/polym12081746.

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In this study, light-responsive nano-assemblies with light-switchable size based on photoacids are presented. Anionic disulfonated napthol derivates and cationic dendrimer macroions are used as building blocks for electrostatic self-assembly. Nanoparticles are already formed under the exclusion of light as a result of electrostatic interactions. Upon photoexcitation, an excited-state dissociation of the photoacidic hydroxyl group takes place, which leads to a more highly charged linker molecule and, subsequently, to a change in size and structure of the nano-assemblies. The effects of the charge ratio and the concentration on the stability have been examined with absorption spectroscopy and ζ-potential measurements. The influence of the chemical structure of three isomeric photoacids on the size and shape of the nanoscale aggregates has been studied by dynamic light scattering and atomic force microscopy, revealing a direct correlation of the strength of the photoacid with the changes of the assemblies upon irradiation.

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Sarkar, Tamal, Brandon A. Kemp et Cheyenne J. Sheppard. « Electrostatic tunability of charged, binary nanoparticle assemblies in dielectric colloidal systems ». Journal of Applied Physics 131, n^o 17 (7 mai 2022) : 175103. http://dx.doi.org/10.1063/5.0085517.

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Charged nanoparticles exhibit anomalous electrostatic interactions, which can lead to stable, non-touching equilibria in inverted dielectric systems. In this study, we analytically demonstrate minimum-potential energy configurations for binary systems of charged nanoparticles and control of constituent spacing by externally applied electrostatic fields. The field–matter interactions are governed by the electrostatic forces of high order multipoles induced by the charged nanoparticles submerged in dielectric liquids. The particles bind in non-touching configurations due to electrostatic potential wells for each particle induced by other dissimilar particles in their vicinity. Such binary systems are proposed as building blocks with the potential of electromagnetic tunability of novel photonic surfaces.

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Mohanta, Kallol, Swarup K. Majee, Sudip K. Batabyal et Amlan J. Pal. « Electrical Bistability in Electrostatic Assemblies of CdSe Nanoparticles ». Journal of Physical Chemistry B 110, n^o 37 (septembre 2006) : 18231–35. http://dx.doi.org/10.1021/jp0639795.

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Gao, Changrui, Honghao Li, Yue Li, Sumit Kewalramani, Liam C. Palmer, Vinayak P. Dravid, Samuel I. Stupp, Monica Olvera de la Cruz et Michael J. Bedzyk. « Electrostatic Control of Polymorphism in Charged Amphiphile Assemblies ». Journal of Physical Chemistry B 121, n^o 7 (10 février 2017) : 1623–28. http://dx.doi.org/10.1021/acs.jpcb.6b11602.

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Osovsky, Ruth, Alexey Shavel, Nikolai Gaponik, Lilac Amirav, Alexander Eychmüller, Horst Weller et Efrat Lifshitz. « Electrostatic and Covalent Interactions in CdTe Nanocrystalline Assemblies ». Journal of Physical Chemistry B 109, n^o 43 (novembre 2005) : 20244–50. http://dx.doi.org/10.1021/jp0526795.

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Zhou, Feng-Lei, Rong-Hua Gong et Isaac Porat. « Mass production of nanofibre assemblies by electrostatic spinning ». Polymer International 58, n^o 4 (avril 2009) : 331–42. http://dx.doi.org/10.1002/pi.2521.

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Ji, Minglei, Lan Jin, Jia Guo, Wuli Yang, Changchun Wang et Shoukuan Fu. « Formation of luminescent nanocomposite assemblies via electrostatic interaction ». Journal of Colloid and Interface Science 318, n^o 2 (février 2008) : 487–95. http://dx.doi.org/10.1016/j.jcis.2007.09.071.

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Düring, Jasmin, Benjamin Butz, Erdmann Spiecker et Franziska Gröhn. « Formation of CdS in Supramolecular Dendrimer–Dye Assemblies : Electrostatic and Electrostatic-Coordination Templating ». Macromolecules 48, n^o 23 (19 novembre 2015) : 8399–411. http://dx.doi.org/10.1021/acs.macromol.5b01165.

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Qian, Weiqiao, Qin Zhu, Bing Duan, Weijun Tang, Yuan Yuan et Aiguo Hu. « Electrostatic self-assembled nanoparticles based on spherical polyelectrolyte brushes for magnetic resonance imaging ». Dalton Transactions 47, n^o 23 (2018) : 7663–68. http://dx.doi.org/10.1039/c8dt01069b.

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Wang, Yuxiang, Xiaojing Li, Fei Li, Wei-Yin Sun, Chengjian Zhu et Yixiang Cheng. « Strong circularly polarized luminescence induced from chiral supramolecular assembly of helical nanorods ». Chemical Communications 53, n^o 54 (2017) : 7505–8. http://dx.doi.org/10.1039/c7cc04363e.

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Hu, Yang, Ran Lin, Pengcheng Zhang, Joshua Fern, Andrew G. Cheetham, Kunal Patel, Rebecca Schulman, Chengyou Kan et Honggang Cui. « Electrostatic-Driven Lamination and Untwisting of β-Sheet Assemblies ». ACS Nano 10, n^o 1 (10 décembre 2015) : 880–88. http://dx.doi.org/10.1021/acsnano.5b06011.

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Mali, Kunal S., et Steven De Feyter. « Principles of molecular assemblies leading to molecular nanostructures ». Philosophical Transactions of the Royal Society A : Mathematical, Physical and Engineering Sciences 371, n^o 2000 (13 octobre 2013) : 20120304. http://dx.doi.org/10.1098/rsta.2012.0304.

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Self-assembled physisorbed monolayers consist of regular two-dimensional arrays of molecules. Two-dimensional self-assembly of organic and metal–organic building blocks is a widely used strategy for nanoscale functionalization of surfaces. These supramolecular nanostructures are typically sustained by weak non-covalent forces such as van der Waals, electrostatic, metal–ligand, dipole–dipole and hydrogen bonding interactions. A wide variety of structurally very diverse monolayers have been fabricated under ambient conditions at the liquid–solid and air–solid interface or under ultra-high-vacuum (UHV) conditions at the UHV–solid interface. The outcome of the molecular self-assembly process depends on a variety of factors such as the nature of functional groups present on assembling molecules, the type of solvent, the temperature at which the molecules assemble and the concentration of the building blocks. The objective of this review is to provide a brief account of the progress in understanding various parameters affecting two-dimensional molecular self-assembly through illustration of some key examples from contemporary literature.

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Agarwal, Mohit, Alexander Zika, Ralf Schweins et Franziska Gröhn. « Controlling the Morphology in Electrostatic Self-Assembly via Light ». Polymers 16, n^o 1 (22 décembre 2023) : 50. http://dx.doi.org/10.3390/polym16010050.

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Electrostatic self-assembly of macroions is an emerging area with great potential in the development of nanoscale functional objects, where photo-irradiation responsiveness can either elevate or suppress the self-assembly. The ability to control the size and shape of macroion assemblies would greatly facilitate the fabrication of desired nano-objects that can be harnessed in various applications such as catalysis, drug delivery, bio-sensors, and actuators. Here, we demonstrate that a polyelectrolyte with a size of 5 nm and multivalent counterions with a size of 1 nm can produce well-defined nanostructures ranging in size from 10–1000 nm in an aqueous environment by utilizing the concept of electrostatic self-assembly and other intermolecular non-covalent interactions including dipole–dipole interactions. The pH- and photoresponsiveness of polyelectrolytes and azo dyes provide diverse parameters to tune the nanostructures. Our findings demonstrate a facile approach to fabricating and manipulating self-assembled nanoparticles using light and neutron scattering techniques.

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Gryn’ova, Ganna, et Clémence Corminboeuf. « Steric “attraction” : not by dispersion alone ». Beilstein Journal of Organic Chemistry 14 (19 juin 2018) : 1482–90. http://dx.doi.org/10.3762/bjoc.14.125.

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Non-covalent interactions between neutral, sterically hindered organic molecules generally involve a strong stabilizing contribution from dispersion forces that in many systems turns the ‘steric repulsion’ into a ‘steric attraction’. In addition to London dispersion, such systems benefit from electrostatic stabilization, which arises from a short-range effect of charge penetration and gets bigger with increasing steric bulk. In the present work, we quantify this contribution for a diverse set of molecular cores, ranging from unsubstituted benzene and cyclohexane to their derivatives carrying tert-butyl, phenyl, cyclohexyl and adamantyl substituents. While the importance of electrostatic interactions in the dimers of sp2-rich (e.g., π-conjugated) cores is well appreciated, less polarizable assemblies of sp3-rich systems with multiple short-range CH···HC contacts between the bulky cyclohexyl and adamantyl moieties are also significantly influenced by electrostatics. Charge penetration is drastically larger in absolute terms for the sp2-rich cores, but still has a non-negligible effect on the sp3-rich dimers, investigated herein, both in terms of their energetics and equilibrium interaction distances. These results emphasize the importance of this electrostatic effect, which has so far been less recognized in aliphatic systems compared to London dispersion, and are therefore likely to have implications for the development of force fields and methods for crystal structure prediction.

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Xian, Yuejiao, Chitra B. Karki, Sebastian Miki Silva, Lin Li et Chuan Xiao. « The Roles of Electrostatic Interactions in Capsid Assembly Mechanisms of Giant Viruses ». International Journal of Molecular Sciences 20, n^o 8 (16 avril 2019) : 1876. http://dx.doi.org/10.3390/ijms20081876.

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In the last three decades, many giant DNA viruses have been discovered. Giant viruses present a unique and essential research frontier for studies of self-assembly and regulation of supramolecular assemblies. The question on how these giant DNA viruses assemble thousands of proteins so accurately to form their protein shells, the capsids, remains largely unanswered. Revealing the mechanisms of giant virus assembly will help to discover the mysteries of many self-assembly biology problems. Paramecium bursaria Chlorella virus-1 (PBCV-1) is one of the most intensively studied giant viruses. Here, we implemented a multi-scale approach to investigate the interactions among PBCV-1 capsid building units called capsomers. Three binding modes with different strengths are found between capsomers around the relatively flat area of the virion surface at the icosahedral 2-fold axis. Furthermore, a capsomer structure manipulation package is developed to simulate the capsid assembly process. Using these tools, binding forces among capsomers were investigated and binding funnels were observed that were consistent with the final assembled capsid. In addition, total binding free energies of each binding mode were calculated. The results helped to explain previous experimental observations. Results and tools generated in this work established an initial computational approach to answer current unresolved questions regarding giant virus assembly mechanisms. Results will pave the way for studying more complicated process in other biomolecular structures.

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Shen, Jiacong, Junqi Sun et Xi Zhang. « Polymeric nanostructured composite films ». Pure and Applied Chemistry 72, n^o 1-2 (1 janvier 2000) : 147–55. http://dx.doi.org/10.1351/pac200072010147.

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This research news describes the construction of polymeric nanostructured composite film based on a variety of interactions, such as hydrophobic–hydrophilic effect, electrostatic interaction, hydrogen bonding, etc. The work focused on developing strategies to solve the basic problems in the area of ultrathin film research, such as stability, improving the interface quality, creating patterned interface, and techniques to construct nanolayered structure. With in-depth study of the relationship between the microscopic layered architecture and macroscopic function of supramolecular assemblies, it is anticipated that one could obtain miniature devices or machines of high efficiency through integration of the assembling process and device fabrication.

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Aakeröy, Christer B., Dhanushi Welideniya et John Desper. « Ethynyl hydrogen bonds and iodoethynyl halogen bonds : a case of synthon mimicry ». CrystEngComm 19, n^o 1 (2017) : 11–13. http://dx.doi.org/10.1039/c6ce02201d.

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The common electrostatic features of ethynyl and iodoethynyl hydrogen- and halogen-bond donors, respectively, lead to synthon mimicry which can be employed in synthetic crystal engineering for the construction of identical supramolecular assemblies in the solid-state.

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Parthasarathy, Barath, Pial Mirdha, Jun Kondo et Faquir Jain. « Dual Quantum Dot Superlattice ». International Journal of High Speed Electronics and Systems 27, n^o 01n02 (mars 2018) : 1840003. http://dx.doi.org/10.1142/s0129156418400037.

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In this paper, we propose a structure using four layers of quantum dots on crystalline silicon. The quantum dots site-specifically self-assembled in the p-type material due to the electrostatic attraction. This quantum dot super lattice (QDSL) structure will be constructed using a mixed layer of Germanium (Ge) and Silicon (Si) dots. Atomic Force Microscopy results will show the accurate stack height formed from individual and multi stacked layers. This is the first novel characterization of 4 layers of 2 separate self assemblies. This was also applied to a quantum dot gate field effect transistor (QDG-FET).

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Ye, Qiang, Dandan Zhu, Lianyi Xu, Xuemin Lu et Qinghua Lu. « The fabrication of helical fibers with circularly polarized luminescence via ionic linkage of binaphthol and tetraphenylethylene derivatives ». Journal of Materials Chemistry C 4, n^o 7 (2016) : 1497–503. http://dx.doi.org/10.1039/c5tc04174k.

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Circularly polarized luminescence material was fabricated by ionic binaphthol and tetraphenylethylene derivatives. Due to electrostatic interactions and chiral induction, the assemblies had a helical fiber structure with a high dissymmetry factor to the order of 10⁻².

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Takahashi, T. « Significant role of electrostatic interactions for stabilization of protein assemblies ». Advances in Biophysics 34 (1997) : 41–54. http://dx.doi.org/10.1016/s0065-227x(97)89630-x.

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Burckbuchler, Virginie, Valérie Boutant, Véronique Wintgens et Catherine Amiel. « Macromolecular Assemblies Based on Coupled Inclusion Complex and Electrostatic Interactions ». Biomacromolecules 7, n^o 10 (octobre 2006) : 2890–900. http://dx.doi.org/10.1021/bm060523k.

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Velichko, Y. S., et M. Olvera de la Cruz. « Electrostatic attraction between cationic-anionic assemblies with surface compositional heterogeneities ». Journal of Chemical Physics 124, n^o 21 (7 juin 2006) : 214705. http://dx.doi.org/10.1063/1.2205854.

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Tian, Fei Yang, Rui Xue Cheng, Yun Qian Zhang, Zhu Tao et Qian Jiang Zhu. « Specific Recognition of Methanol Using a Symmetric Tetramethylcucurbit[6]uril-Based Porous Supramolecular Assembly Incorporating Adsorbed Dyes ». Australian Journal of Chemistry 73, n^o 11 (2020) : 1065. http://dx.doi.org/10.1071/ch19586.

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A symmetric tetramethylcucurbit[6]uril-based porous supramolecular assembly was prepared in an aqueous H2SO4 solution (5M). The driving force for the formation of this assembly is mainly the outer surface interaction of Q[n], which includes the ion-dipole interaction of SO42− anions and the positive electrostatic potential of the outer surface of the symmetric tetramethylcucurbit[6]uril (TMeQ[6]), the dipole-dipole interactions between the positive electrostatic potential of the outer surface of TMeQ[6] and portal carbonyl oxygens of TMeQ[6], and the hydrogen bonding between lattice water molecules and portal carbonyl oxygen atoms in TMeQ[6]. The TMeQ[6]-based porous supramolecular assembly exhibits the characteristics of absorbed fluorophore guests (FGs), such as dyes and polycyclic compounds with different fluorescence characteristics. Moreover, the resulting luminescent assemblies (FG@As) can respond to certain volatile organic compounds; in particular, the luminescent assemblies of rhodamine B or pyrene display a unique fluorescence enhancement in response to methanol.

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Dick, Nir, et Slava Krylov. « Modal Behavior of Microcantilevers Arrays with Tunable Electrostatic Coupling ». Actuators 12, n^o 10 (13 octobre 2023) : 386. http://dx.doi.org/10.3390/act12100386.

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We analyse the spectral content and parametric resonant dynamics of an array of elastically and electrostatically coupled interdigitated micro cantilevers assembled into two identical half-arrays. In this uncommon arrangement, within each of the half-arrays, the beams are coupled only elastically. The half-arrays are intercoupled only electrostatically, through fringing fields. First, by using the reduced order (RO) model, we analyse the voltage-dependent evolution of the eigenvalues and the eigenvectors of the equivalent mass-spring system, starting from the small two, three and four beams arrays and up to large beams assemblies. We show that at the coupling voltages below a certain critical value, the shape of the eigenvectors, the frequencies of the veering and of the crossing are influenced by the electrostatic coupling and can be tuned by the voltage. Next, by implementing the assumed modes techniques we explore the parametric resonant behavior of the array. We show that in the case of the sub critical electrostatic coupling the actuating voltages required to excite parametric resonance in the damped system can be lower than in a strongly coupled array. The results of the work may inspire new designs of more efficient resonant sensors.

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Ye, Feng, Jinhua Yang, Weiwei Hu, Hui Liu, Shijun Liao, Jianhuang Zeng et Jun Yang. « Electrostatic interaction based hollow Pt and Ru assemblies toward methanol oxidation ». RSC Advances 2, n^o 19 (2012) : 7479. http://dx.doi.org/10.1039/c2ra21140h.

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Balbinot, Domenico, Stefan Atalick, Dirk M. Guldi, Maria Hatzimarinaki, Andreas Hirsch et Norbert Jux. « Electrostatic Assemblies of Fullerene−Porphyrin Hybrids : Toward Long-Lived Charge Separation ». Journal of Physical Chemistry B 107, n^o 48 (décembre 2003) : 13273–79. http://dx.doi.org/10.1021/jp0304780.

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Menger, Fredric M., et Lei Shi. « Electrostatic Binding among Equilibrating 2-D and 3-D Self-Assemblies ». Journal of the American Chemical Society 131, n^o 19 (20 mai 2009) : 6672–73. http://dx.doi.org/10.1021/ja902174g.

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Guldi, Dirk M., et Maurizio Prato. « Electrostatic interactions by design. Versatile methodology towards multifunctional assemblies/nanostructured electrodes ». Chemical Communications, n^o 22 (2004) : 2517. http://dx.doi.org/10.1039/b410541a.

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Bock, H., R. C. Advincula, E. F. Aust, J. Käshammer, W. H. Meyer, S. Mittler-Neher, C. Fiorini, J. M. Nunzi et W. Knoll. « Supramolecular Assemblies for Second Order Nonlinear Optics Stabilized by Electrostatic Interaction ». Journal of Nonlinear Optical Physics & ; Materials 07, n^o 03 (septembre 1998) : 385–95. http://dx.doi.org/10.1142/s0218863598000296.

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Electrostatic interactions are being used instead of covalent linkage to stabilize orientational order in novel materials for second order nonlinear optics. In complex supramolecular architectures, this simplifies the variation of chromophores or polymeric backbones. Other molecules can readily be inserted into the system in order to tune optical or thermodynamic properties without synthetic effort. Noncentrosymmetric ultrathin films consisting of highly ordered "active-passive" AB-Y-type multilayers of NLO active ionic amphiphiles and an ionic polymeric buffer material have been obtained by the Langmuir-Blodgett-Kuhn (LBK) technique. Combination with self-assembly by adsorption from solution is demonstrated.

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Aslandaş, Ayşe Merve, Yavuz Onganer et Kadem Meral. « Polyelectrolytes-assisted layer-by-layer assemblies of graphene oxide and dye on glass substrate ». RSC Advances 5, n^o 23 (2015) : 18051–56. http://dx.doi.org/10.1039/c4ra16921b.

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Zika, Alexander, et Franziska Gröhn. « Multiswitchable photoacid–hydroxyflavylium–polyelectrolyte nano-assemblies ». Beilstein Journal of Organic Chemistry 17 (19 janvier 2021) : 166–85. http://dx.doi.org/10.3762/bjoc.17.17.

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Light- and pH-responsive nano-assemblies with switchable size and structure are formed by the association of a photoacid, anthocyanidin, and a linear polyelectrolyte in aqueous solution. Specifically, anionic disulfonated naphthol derivatives, neutral hydroxyflavylium, and cationic poly(allylamine) are used as building blocks for the ternary electrostatic self-assembly, forming well-defined supramolecular assemblies with tunable sizes of 50 to 500 nm. Due to the network of possible chemical reactions for the anthocyanidin and the excited-state dissociation of the photoacid upon irradiation, different ways to alter the ternary system through external triggering are accessible. The structure and trigger effects can be controlled through the component ratios of the samples. Dynamic and static light scattering (DLS, SLS) and ζ-potential measurements were applied to study the size and the stability of the particles, and information on the molecular structure was gained by UV–vis spectroscopy. Isothermal titration calorimetry (ITC) provided information on the thermodynamics and interaction forces in the supramolecular assembly formation.

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Gao, Holkar et Srivastava. « Protein–Polyelectrolyte Complexes and Micellar Assemblies ». Polymers 11, n^o 7 (28 juin 2019) : 1097. http://dx.doi.org/10.3390/polym11071097.

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In this review, we highlight the recent progress in our understanding of the structure, properties and applications of protein–polyelectrolyte complexes in both bulk and micellar assemblies. Protein–polyelectrolyte complexes form the basis of the genetic code, enable facile protein purification, and have emerged as enterprising candidates for simulating protocellular environments and as efficient enzymatic bioreactors. Such complexes undergo self-assembly in bulk due to a combined influence of electrostatic interactions and entropy gains from counterion release. Diversifying the self-assembly by incorporation of block polyelectrolytes has further enabled fabrication of protein–polyelectrolyte complex micelles that are multifunctional carriers for therapeutic targeted delivery of proteins such as enzymes and antibodies. We discuss research efforts focused on the structure, properties and applications of protein–polyelectrolyte complexes in both bulk and micellar assemblies, along with the influences of amphoteric nature of proteins accompanying patchy distribution of charges leading to unique phenomena including multiple complexation windows and complexation on the wrong side of the isoelectric point.

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Maeda, Hiromitsu. « Ordered Arrangement of Charged Porphyrins in π-Electronic Ion-Pairing Assemblies ». ECS Meeting Abstracts MA2022-01, n^o 14 (7 juillet 2022) : 982. http://dx.doi.org/10.1149/ma2022-0114982mtgabs.

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π-Electronic ions with appropriate geometries and peripheral substituents provide assemblies through the interactions between charged building subunits, resulting in fascinating electronic properties. Structures and properties of the assemblies can be controlled by the combined negatively and positively charged species in the assemblies. Thus far, diverse π-electronic ions along with ion-responsive π-electronic systems have afforded dimension-controlled ion-pairing assemblies as crystals, supramolecular gels, and thermotropic liquid crystals.[1] Highly ordered arrangement of charged species has been found to be a key factor to exhibit the enhanced performance as fascinating electronic materials. In fact, ion pairs of porphyrin–AuIII complexes as π-electronic cations, prepared with the combination of various anions including π-electronic anions, formed dimension-controlled assemblies as thermotropic liquid crystals, whose ionic components were highly organized by i π– i π interactions (mainly electrostatic and dispersion forces).[2] Furthermore, π-electronic ion pairs comprising porphyrin-based π-electronic anions[3] have exhibited characteristic assembling modes via i π– i π interactions and resulting electronic properties such as solid-state absorption, which was correlated with the arrangement of constituent charged π-systems, and photoinduced electron transfer.[4] References [1] Recent reviews: (a) Haketa, Y. et al. Mol. Syst. Des. Eng. 2020, 5, 757; (b) Yamasumi, K. et al. Bull. Chem. Soc. Jpn. 2021, 94, 2252. [2](a) Haketa, H. et al. iScience 2019, 14, 241; (b) Tanaka, H. et al. Chem. Asian J. 2019, 14, 2129; (c) Tanaka, H. et al. Chem. Asian J. 2020, 15, 494; (d) Fumuto, N. et al. Org. Lett. 2021, 23, 3897; (e) Kuno, A. et al. Chem. Eur. J. 2021, 27, 10068. [3](a) Sasano, Y. et al. Dalton Trans. 2017, 46, 8924. (b) Sasano, Y. et al. Chem. Eur. J. 2019, 25, 6712. [4] Sasano, Y.; Tanaka, H. et al. Chem. Sci. 2021, 12, 9645.

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Wakabayashi, Rie, Ayato Higuchi, Hiroki Obayashi, Masahiro Goto et Noriho Kamiya. « pH-Responsive Self-Assembly of Designer Aromatic Peptide Amphiphiles and Enzymatic Post-Modification of Assembled Structures ». International Journal of Molecular Sciences 22, n^o 7 (27 mars 2021) : 3459. http://dx.doi.org/10.3390/ijms22073459.

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Supramolecular fibrous materials in biological systems play important structural and functional roles, and therefore, there is a growing interest in synthetic materials that mimic such fibrils, especially those bearing enzymatic reactivity. In this study, we investigated the self-assembly and enzymatic post-modification of short aromatic peptide amphiphiles (PAs), Fmoc-LnQG (n = 2 or 3), which contain an LQG recognition unit for microbial transglutaminase (MTG). These aromatic PAs self-assemble into fibrous structures via π-π stacking interactions between the Fmoc groups and hydrogen bonds between the peptides. The intermolecular interactions and morphologies of the assemblies were influenced by the solution pH because of the change in the ionization states of the C-terminal carboxy group of the peptides. Moreover, MTG-catalyzed post-modification of a small fluorescent molecule bearing an amine group also showed pH dependency, where the enzymatic reaction rate was increased at higher pH, which may be because of the higher nucleophilicity of the amine group and the electrostatic interaction between MTG and the self-assembled Fmoc-LnQG. Finally, the accumulation of the fluorescent molecule on these assembled materials was directly observed by confocal fluorescence images. Our study provides a method to accumulate functional molecules on supramolecular structures enzymatically with the morphology control.

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Mertsalov, Dmitriy F., Rosa M. Gomila, Vladimir P. Zaytsev, Mikhail S. Grigoriev, Eugeniya V. Nikitina, Fedor I. Zubkov et Antonio Frontera. « On the Importance of Halogen Bonding Interactions in Two X-ray Structures Containing All Four (F, Cl, Br, I) Halogen Atoms ». Crystals 11, n^o 11 (18 novembre 2021) : 1406. http://dx.doi.org/10.3390/cryst11111406.

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This manuscript reports the synthesis and X-ray characterization of two octahydro-1H-4,6-epoxycyclopenta[c]pyridin-1-one derivatives that contain the four most abundant halogen atoms (Ha) in the structure with the aim of studying the formation of Ha···Ha halogen bonding interactions. The anisotropy of electron density at the heavier halogen atoms provokes the formation of multiple Ha···Ha contacts in the solid state. That is, the heavier Ha-atoms exhibit a region of positive electrostatic potential (σ-hole) along the C–Ha bond and a belt of negative electrostatic potential (σ-lumps) around the atoms. The halogen bonding assemblies in both compounds were analyzed using density functional theory (DFT) calculations, molecular electrostatic potential (MEP) surfaces, the quantum theory of “atom-in-molecules” (QTAIM), the noncovalent interaction plot (NCIplot), and the electron localization function (ELF).

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Shi, Nan, Junyan Tan, Xinhua Wan, Yan Guan et Jie Zhang. « Induced salt-responsive circularly polarized luminescence of hybrid assemblies based on achiral Eu-containing polyoxometalates ». Chemical Communications 53, n^o 31 (2017) : 4390–93. http://dx.doi.org/10.1039/c7cc01586k.

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Coassemblies of chiral cationic block polymers and achiral anionic Eu-POMs through electrostatic interactions display salt-responsive induced circularly polarized luminescence, which arises from the static coupling and dynamic coupling.

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Willerich, Immanuel, et Franziska Gröhn. « Molecular Structure Encodes Nanoscale Assemblies : Understanding Driving Forces in Electrostatic Self-Assembly ». Journal of the American Chemical Society 133, n^o 50 (21 décembre 2011) : 20341–56. http://dx.doi.org/10.1021/ja207565m.

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Yang, Yang, et Keisaku Kimura. « Preparation of Ag Nanoparticle Assemblies at Air–Water Interface by Electrostatic Interaction ». Chemistry Letters 35, n^o 3 (mars 2006) : 296–97. http://dx.doi.org/10.1246/cl.2006.296.

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Kim, Myunghwan, et D. J. Sandman. « POLYCATION EFFECTS ON ELECTRONIC SPECTRA OF CONJUGATED POLYMERS IN PROGRAMMED ELECTROSTATIC ASSEMBLIES ». Journal of Macromolecular Science, Part A 38, n^o 12 (30 novembre 2001) : 1291–304. http://dx.doi.org/10.1081/ma-100108384.

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Díez-Pascual, Ana, et Abbas Rahdar. « LbL Nano-Assemblies : A Versatile Tool for Biomedical and Healthcare Applications ». Nanomaterials 12, n^o 6 (14 mars 2022) : 949. http://dx.doi.org/10.3390/nano12060949.

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Polyelectrolytes (PEs) have been the aim of many research studies over the past years. PE films are prepared by the simple and versatile layer-by-layer (LbL) approach using alternating assemblies of polymer pairs involving a polyanion and a polycation. The adsorption of the alternating PE multiple layers is driven by different forces (i.e., electrostatic interactions, H-bonding, charge transfer interactions, hydrophobic forces, etc.), which enable an accurate control over the physical properties of the film (i.e., thickness at the nanoscale and morphology). These PE nano-assemblies have a wide range of biomedical and healthcare applications, including drug delivery, protein delivery, tissue engineering, wound healing, and so forth. This review provides a concise overview of the most outstanding research on the design and fabrication of PE nanofilms. Their nanostructures, molecular interactions with biomolecules, and applications in the biomedical field are briefly discussed. Finally, the perspectives of further research directions in the development of LbL nano-assemblies for healthcare and medical applications are highlighted.

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Nascimbeni, Giulia, Christof Wöll et Egbert Zojer. « Electrostatic Design of Polar Metal–Organic Framework Thin Films ». Nanomaterials 10, n^o 12 (3 décembre 2020) : 2420. http://dx.doi.org/10.3390/nano10122420.

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In recent years, optical and electronic properties of metal–organic frameworks (MOFs) have increasingly shifted into the focus of interest of the scientific community. Here, we discuss a strategy for conveniently tuning these properties through electrostatic design. More specifically, based on quantum-mechanical simulations, we suggest an approach for creating a gradient of the electrostatic potential within a MOF thin film, exploiting collective electrostatic effects. With a suitable orientation of polar apical linkers, the resulting non-centrosymmetric packing results in an energy staircase of the frontier electronic states reminiscent of the situation in a pin-photodiode. The observed one dimensional gradient of the electrostatic potential causes a closure of the global energy gap and also shifts core-level energies by an amount equaling the size of the original band gap. The realization of such assemblies could be based on so-called pillared layer MOFs fabricated in an oriented fashion on a solid substrate employing layer by layer growth techniques. In this context, the simulations provide guidelines regarding the design of the polar apical linker molecules that would allow the realization of MOF thin films with the (vast majority of the) molecular dipole moments pointing in the same direction.

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Varadwaj, Pradeep, Arpita Varadwaj, Helder Marques et Koichi Yamashita. « Can Combined Electrostatic and Polarization Effects Alone Explain the F···F Negative-Negative Bonding in Simple Fluoro-Substituted Benzene Derivatives ? A First-Principles Perspective ». Computation 6, n^o 4 (20 septembre 2018) : 51. http://dx.doi.org/10.3390/computation6040051.

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The divergence of fluorine-based systems and significance of their nascent non-covalent chemistry in molecular assemblies are presented in a brief review of the field. Emphasis has been placed to show that type-I and -II halogen-centered F···F long-ranged intermolecular distances viable between the entirely negative fluorine atoms in some fluoro-substituted dimers of C6H6 can be regarded as the consequence of significant non-covalent attractive interactions. Such attractive interactions observed in the solid-state structures of C6F6 and other similar fluorine-substituted aromatic compounds have frequently been underappreciated. While these are often ascribed to crystal packing effects, we show using first-principles level calculations that these are much more fundamental in nature. The stability and reliability of these interactions are supported by their negative binding energies that emerge from a supermolecular procedure using MP2 (second-order Møller-Plesset perturbation theory), and from the Symmetry Adapted Perturbation Theory, in which the latter does not determine the interaction energy by computing the total energy of the monomers or dimer. Quantum Theory of Atoms in Molecules and Reduced Density Gradient Non-Covalent Index charge-density-based approaches confirm the F···F contacts are a consequence of attraction by their unified bond path (and bond critical point) and isosurface charge density topologies, respectively. These interactions can be explained neither by the so-called molecular electrostatic surface potential (MESP) model approach that often demonstrates attraction between sites of opposite electrostatic surface potential by means of Coulomb’s law of electrostatics, nor purely by the effect of electrostatic polarization. We provide evidence against the standalone use of this approach and the overlooking of other approaches, as the former does not allow for the calculation of the electrostatic potential on the surfaces of the overlapping atoms on the monomers as in the equilibrium geometry of a complex. This study thus provides unequivocal evidence of the limitation of the MESP approach for its use in gaining insight into the nature of reactivity of overlapped interacting atoms and the intermolecular interactions involved.

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Xu, Huifang, Xin Liang, Song Lu, Meihua Gao, Sijia Wang et Yuanyuan Li. « Self-Assembly of Palmitic Acid in the Presence of Choline Hydroxide ». Molecules 28, n^o 22 (7 novembre 2023) : 7463. http://dx.doi.org/10.3390/molecules28227463.

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To disperse fatty acids in aqueous solution, choline, a quaternary ammonium ion, has been used recently. So far, only the self-assembly of myristic acid (MA) in the presence of choline hydroxide as a function of the molar ratio has been investigated, and, thus, the current understanding of these fatty acid systems is still limited. We investigated the self-assembly of palmitic acid (PA) in the presence of choline hydroxide (ChOH) as a function of the molar ratio (R) between ChOH and PA. The self-assemblies were characterized by phase contrast microscopy, cryo-TEM, small-angle X-ray scattering, and 2H NMR. The ionization state of PA was determined by pH, conductivity, and FT-IR measurements. With increase in R, various self-assembled structures, including vesicles, lamellar phase, rigid membranes (large sheets, tubules, cones, and polyhedrals), and micelles, form in the PA/ChOH system, different from those of the MA/ChOH system. The change in R induces pH variation and, consequently, a change in the PA ionization state, which, in turn, regulates the molecular interactions, including hydrogen bonding and electrostatic interaction, leading to various self-assemblies. Temperature is an important factor used to tune the self-assembly transitions. The fatty acid choline systems studied here potentially may be applicable in medicine, chemical engineering, and biotechnology.

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Babut, Thomas, Mona Semsarilar, Marc Rolland et Damien Quemener. « Nano-Fibrous Networks from Co-Assembly of Amphiphilic Peptide and Polyelectrolyte ». Polymers 13, n^o 22 (18 novembre 2021) : 3983. http://dx.doi.org/10.3390/polym13223983.

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Organize the matter on an increasingly small scale is sought in order to increase the performance of materials. In the case of porous materials, such as filtration membranes, a compromise must be found between the selectivity provided by this nanostructuring and a permeability in particular linked to the existing pore volume. In this work, we propose an innovative waterborne approach consisting in co-assembling peptide amphiphiles (PA) which will provide nanostructuring and polyelectrolytes which will provide them with sufficient mechanical properties to sustain water pressure. C16-V3A3K3G-NH2 PA nanocylinders were synthesized and co-assembled with poly(sodium 4-styrenesulfonate) (PSSNa) into porous nano-fibrous network via electrostatic interactions. The ratio between C16-V3A3K3G-NH2 and PSSNa was studied to optimize the material structure. Since spontaneous gelation between the two precursors does not allow the material to be shaped, various production methods have been studied, in particular via tape casting and spray-coating. Whereas self-supported membranes were mechanically weak, co-assemblies supported onto commercial ultrafiltration membranes could sustain water pressure up to 3 bars while a moderate permeability was measured confirming the existence of a percolated network. The produced membrane material falls into the ultrafiltration range with a pore radius of about 7.6 nm.

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Quinn, John F., et Frank Caruso. « Stabilization of Hydrogen-Bonded Poly(N-isopropylacrylamide) Multilayers by a Dual Electrostatic/Hydrogen Bonding Copolymer ». Australian Journal of Chemistry 58, n^o 6 (2005) : 442. http://dx.doi.org/10.1071/ch05052.

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Multilayer thin films were prepared based on hydrogen bonding between poly(N-isopropylacrylamide) (PNiPAAm), and poly(styrene sulfonate-co-maleic acid) (PSSMA). Since PSSMA is capable of associating with other polymers through both hydrogen bonding and electrostatic interactions, multilayer assemblies incorporating PSSMA, PNiPAAm, and intercalated poly(allylamine hydrochloride) (PAH) layers were also prepared. Intercalated PAH layers were included to improve the pH stability of the film by introducing electrostatic linkages into the assembly. Film construction was studied as a function of pH of the deposition solution and the number of inserted PAH layers. Film morphology varied significantly with incorporation of PAH into the film. It was also demonstrated that by intercalating several PAH layers within the PNiPAAm/PSSMA assembly, the pH stability of the films at pH 5.8 could be substantially improved.

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