Self-assembled molecular network formed by controlling molecular deposition of organic compounds
Graphical abstract
Introduction
The noncovalent assembly of functional molecules into well-ordered supramolecular structures on a solid surface is of critical importance because it facilities efficient control of the spatial organization of molecular size and the functionalities of the molecular structures [1], [2]. These molecular structures can be formed by the self-assembly of small organic molecules on different substrates such as metals, insulators, semiconductors, and layered materials, which act as physical supports. In most cases, these self-assemblies are limited to the formation of a specific pattern and multilayer termination [3], [4], [5], [6], [7], [8], [9]. However, the conventional methods for self-assembly functional molecules from saturated solutions or suspensions require additional processing steps after deposition, such as the addition of an organic solvent, evaporation, and temperature or pH modulation [10]. Bottom-up strategies, including template-based design techniques, electrospinning, spin-coating self-assembly, evaporation-induced self-assembly, and hydrothermal methods do not allow for successful control of the material properties over the surface coverage or layer structure. Thus, there is a strong motivation to discover more complex materials derived from stacked supramolecular networks [10], [11], [12], [13], [14], [15], [16], [17]. Herein, we describe the self-assembly of PMA molecules using a combination of plasma electrolytic oxidation (PEO) and ultrahigh-vacuum physical vapor deposition (UHV-PVD). Furthermore, we performed density functional theory (DFT) calculations to confirm the experimental results and deepen our understanding of the nature of the complex interactions in the self-assembly.
We selected a combination of inorganic layers designed by PEO and an organic layer (OL) prepared by UVH-PVD, where pyromellitic acid (PMA) was used as the organic component. The metal-oxide and metal-aluminate system (MgO-MgAl2O4) was prepared by PEO in an alkaline solution. Subsequently, inorganic layer (IL) was used as the substrate for the deposition of the PMA molecules, which were adsorbed onto porous materials to form a homostructure. An OL was deposited on a porous metal-oxide platform via the sequential evaporation of PMA molecules under UHV conditions. Our previous report revealed that these substrates support self-assembly via the dip chemical coating (DCC) method [16], [17], [18].
Section snippets
Preparation of HOI materials
The inorganic layer was prepared by subjecting a commercial AZ31 Mg alloy (chemical composition: Al = 3.08, Zn = 0.76, Mn = 0.15, and Mg: balanced (wt.%)) to PEO under 60 Hz AC current for 400 s in a solution comprising KOH (6 g/L), and NaAlO2 (8 g/L) at a density of 100 mA cm−2. For HOI materials, PMA (0.7 g, C10H6O8) self-assembled was performed on the MgO-MgAl2O4 layer (30 × 15 cm3) using a UHV-PVD system (Model: HINHIVAC 12′’ vacuum coating unit, 12A4D) with multideposition under different
Surface morphology of PMA/Mg2AlO4-MgO
The PMA molecules were deposited in the gas phase (7 × 10−6 Torr) on the porous IL (Fig. 1a) at different voltages (0.10, 0.25, and 0.30 V) through UHV-PVD (Fig. 1b–d) at 6 min. The degree of aggregation of the PMA molecules on the IL surface increased with increasing operating voltage, and the surface porosity at 0.10, 0.25, and 0.30 V was found to be 23 ± 1.1%, 20 ± 1.5%, and 15 ± 1.7%, respectively. Interestingly, self-assembly of PMA molecules was formed over the IL, creating self-assembly
Conclusions
This study reports that self-assembly of PMA molecules on a porous inorganic layer can be achieved by a novel strategy involving sequential deposition of organic molecules with high corrosion resistance. The inorganic layer prepared by PEO exhibited micropores and microcracks that aided the deposition of PMA molecules and strengthened the physical bonding between the organic and inorganic components. The use of UHV-PVD promises a high degree of control over the growing film and allows for in
CRediT authorship contribution statement
Wail Al Zoubi: Conceptualization, Methodology, Investigation, Formal analysis, Writing - original draft. Nisa Nashrah: Writing - original draft. Abdelkarim Chaouiki: Formal analysis. Young Gun Ko: Supervision, Funding acquisition, Writing - review & editing.
Declaration of Competing Interest
The authors declare that they have no known competing interests or personal relationships that could have appeared to influence the work reported in this paper.
Acknowledgements
This work is supported by the Mid-Level Researcher National Project of the National Research Foundation funded by the Ministry of Science and ICT, Republic of Korea (NRF-2020R1A2C2004192). Y.G.K. acknowledges G.Y.H. for the fruitful discussion on review work.
References (39)
- et al.
Recent advances in hybrid organic-inorganic materials with spatial architecture for state-of-the art applications
Prog. Mater Sci.
(2020) - et al.
Dual-functional crosslinked polymer-inorganic materials for robust electrochemcial performance and anitbacterial activity
Chem. Eng. J.
(2020) - et al.
Simple hydrothermal synthesis of ordered mesoporous carbons from resorcinol and hexamine
Carbon
(2011) - et al.
Self-assembly of hierarchical N-heterocycles-inorganic materials into three-dimensional structure for superior corrosion protection
Chem. Eng. J.
(2019) - et al.
Fabrication of graphene oxide/8-hyroquinolin/inorganic coating on the magnesium surface for extraordinary corrosion protection
Prog. Org. Coat.
(2019) - et al.
Molecular structures in the inorganic metal interaction for optimizing electrochemcial performance
J. Mol. Liq.
(2021) - et al.
Plasma electrolytic oxidation coatings on cp-Mg with cerium nitrate and benzotriazole immersion post-treatments
Surf. Coat. Technol.
(2018) - et al.
ZrO2/TiO2 films prepared by plasma electrolytic oxidation and pot treatment
Surf. Coat. Technol.
(2017) - et al.
Self-assembled four-membered network of trimesic acid forming organic channel structure
J. Mol. Struct.
(2000) - et al.
Characteristic of ceramic coatings on aluminum by plasma electrolytic oxidation in silicate and phosphate electrolyte
App. Surf. Sci.
(2006)
Mechanism study about the adsorption of Pb(II) and Cd(II) with iron-trimesic metal-organic frameworks
Chem. Eng. J.
Modification of tantalum surface via plasma electrolytic oxidation in silicate solutions
Electrochim. Acta
Characteristics and corrosion resistance of plasma electrolytic oxidation coatings on AZ31B Mg alloy formed in phosphate-silicate mixture electrolytes
Corrs. Sci.
A self-adjusting PTFE/TiO2 hydrophobic double-layer coating for corrosion resistance and electrical insulation
Chem. Eng. J.
Supramolecular heterostructures formed by sequential epitaxial deposition of two-dimensional hydrogen-bonded arrays
Nat. Chem.
Controlling molecular deposition and layer structure with supramolecular surface assemblies
Nature
Building supramolecular nanostructures at surfaces by hydrogen bonding
Angew. Chem. Int. Ed.
Reaction of aniline with chemisorbed pyromellitic dianhydride on Cu(110): a model for controlled organic film growth
Surf. Interface Anal.
Robust and open tailored supramolecular networks controlled by the template effect of a silicon surface
Angew. Chem. Int. Ed.
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