scholarly journals Electrostatic Interactions for Bottom Up Assembly of Two-Dimensional Nanostructures

2011 ◽  
Author(s):  
Brigid R. Heywood ◽  
S. Champ

Recent work on the crystallisation of inorganic crystals under compressed monomolecular surfactant films has shown that two dimensional templates can be used to promote the oriented nucleation of solids. When a suitable long alkyl chain surfactant is cast on the crystallisation media a monodispersied population of crystals forms exclusively at the monolayer/solution interface. Each crystal is aligned with a specific crystallographic axis perpendicular to the plane of the monolayer suggesting that nucleation is facilitated by recognition events between the nascent inorganic solid and the organic template.For example, monolayers of the long alkyl chain surfactant, stearic acid will promote the oriented nucleation of the calcium carbonate polymorph, calcite, on the (100) face, whereas compressed monolayers of n-eicosyl sulphate will induce calcite nucleation on the (001) face, (Figure 1 & 2). An extensive program of research has confirmed the general principle that molecular recognition events at the interface (including electrostatic interactions, geometric homology, stereochemical complementarity) can be used to promote the crystal engineering process.


2021 ◽  
Author(s):  
Subrata Pandit ◽  
Mrinmoy De

The synthesis of two-dimensional (2D) nanosheets such as graphene and their derivatives through bottom-up approach has many advantages such as growth control and functionalization, but it is always challenging to...


Processes ◽  
2020 ◽  
Vol 8 (5) ◽  
pp. 504 ◽  
Author(s):  
Siyi Huang ◽  
Ziyun You ◽  
Yanting Jiang ◽  
Fuxiang Zhang ◽  
Kaiyang Liu ◽  
...  

Owing to their peculiar structural characteristics and potential applications in various fields, the ultrathin MoS2 nanosheets, a typical two-dimensional material, have attracted numerous attentions. In this paper, a hybrid strategy with combination of quenching process and liquid-based exfoliation was employed to fabricate the ultrathin MoS2 nanosheets (MoS2 NS). The obtained MoS2 NS still maintained hexagonal phase (2H-MoS2) and exhibited evident thin layer-structure (1–2 layers) with inconspicuous wrinkle. Besides, the MoS2 NS dispersion showed excellent stability (over 60 days) and high concentration (0.65 ± 0.04 mg mL−1). The MoS2 NS dispersion also displayed evident optical properties, with two characteristic peaks at 615 and 670 nm, and could be quantitatively analyzed with the absorbance at 615 nm in the range of 0.01–0.5 mg mL−1. The adsorption experiments showed that the as-prepared MoS2 NS also exhibited remarkable adsorption performance on the dyes (344.8 and 123.5 mg g−1 of qm for methylene blue and methyl orange, respectively) and heavy metals (185.2, 169.5, and 70.4 mg g−1 of qm for Cd2+, Cu2+, and Ag+). During the adsorption, the main adsorption mechanisms involved the synergism of physical hole-filling effects and electrostatic interactions. This work provided an effective way for the large-scale fabrication of the two-dimensional nanosheets of transition metal dichalcogenides (TMDs) by liquid exfoliation.


2018 ◽  
Vol 6 (18) ◽  
pp. 4919-4927 ◽  
Author(s):  
Tao Zhang ◽  
Raul D. Rodriguez ◽  
Ihsan Amin ◽  
Jacek Gasiorowski ◽  
Mahfujur Rahaman ◽  
...  

The covalent attachment of a one dimensional (1D) polymer brush onto a two-dimensional (2D) material presents an appealing strategy to fabricate anisotropic polymer membranes, namely “polymer carpets”.


2019 ◽  
Vol 141 (42) ◽  
pp. 16755-16762 ◽  
Author(s):  
Kun Lan ◽  
Qiulong Wei ◽  
Ruicong Wang ◽  
Yuan Xia ◽  
Shuangshuang Tan ◽  
...  

2019 ◽  
Vol 14 (23) ◽  
pp. 4400-4407 ◽  
Author(s):  
Takahiro Kojima ◽  
Takahiro Nakae ◽  
Zhen Xu ◽  
Chinnusamy Saravanan ◽  
Kentaro Watanabe ◽  
...  

Author(s):  
KATSUSHI INOUE ◽  
ITSUO SAKURAMOTO ◽  
MAKOTO SAKAMOTO ◽  
ITSUO TAKANAMI

This paper deals with two topics concerning two-dimensional automata operating in parallel. We first investigate a relationship between the accepting powers of two-dimensional alternating finite automata (2-AFAs) and nondeterministic bottom-up pyramid cellular acceptors (NUPCAs), and show that Ω ( diameter × log diameter ) time is necessary for NUPCAs to simulate 2-AFAs. We then investigate space complexity of two-dimensional alternating Turing machines (2-ATMs) operating in small space, and show that if L (n) is a two-dimensionally space-constructible function such that lim n → ∞ L (n)/ loglog n > 1 and L (n) ≤ log n, and L′ (n) is a function satisfying L′ (n) =o (L(n)), then there exists a set accepted by some strongly L (n) space-bounded two-dimensional deterministic Turing machine, but not accepted by any weakly L′ (n) space-bounded 2-ATM, and thus there exists a rich space hierarchy for weakly S (n) space-bounded 2-ATMs with loglog n ≤ S (n) ≤ log n.


2012 ◽  
Vol 68 (9) ◽  
pp. o355-o358 ◽  
Author(s):  
Jun Xue ◽  
Cui-Cui Zhao ◽  
Zi-Yi Du

Cocrystallization of melamine (1,3,5-triazine-2,4,6-triamine, ma) with (2-carboxyethyl)(phenyl)phosphinic acid (H2L) from water affords the title compound, C3H7N6+·C9H10O4P−·H2O or (maH)(HL)·H2O, (I). The phosphinic acid H atom of each H2Lmolecule is transferred to a melamine molecule. Structural analysis reveals that there are two types of secondary building units in the crystal structure, namely cationic [(maH+)2]∞ribbons and anionic {[(HL)2(H2O)2]2−}∞layers, the combination of which through hydrogen-bond and electrostatic interactions, generates a large-scale two-dimensional layered structure. The thick layer is sandwich-like, with the central [(maH+)2]∞ribbons being further stabilized by π–π stacking interactions. It is also worthy of note that two conformational isomericR65(24) hydrogen-bond ring motifs can be identified in the {[(HL)2(H2O)2]2−}∞layer.


ACS Nano ◽  
2010 ◽  
Vol 4 (4) ◽  
pp. 1813-1820 ◽  
Author(s):  
Sebastian Stepanow ◽  
Robin Ohmann ◽  
Frederic Leroy ◽  
Nian Lin ◽  
Thomas Strunskus ◽  
...  

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