Controlled self-assembly of polymer semiconductors in solution using a solvent-vapor approach

2019 ◽  
Vol 33 (14n15) ◽  
pp. 1940038
Author(s):  
Gyounglyul Jo ◽  
Solip Choi ◽  
Jae Won Jeong ◽  
Gyun Taek Lim ◽  
Jaehan Jung ◽  
...  
Keyword(s):  
Self Assembly ◽  
Solution Treatment ◽  
Molecular Assembly ◽  
Solvent Vapor ◽  
Force Microscopy ◽  
Polymer Semiconductors ◽  
Molecular Ordering ◽  
Vis Spectroscopy ◽  
Self Assembled ◽  
Solvent Molecules

A facile solution treatment strategy for controlling the microstructure of conjugated polymers using a non-solvent vapor is introduced. The content of well-ordered poly(3-hexylthiophene) (P3HT) aggregates in solution was precisely controlled by varying the non-solvent vapor exposure time. P3HT chains were self-assembled upon exposure to the non-solvent vapor to minimize the unfavorable interactions with the non-solvent molecules. The effect of solvent vapor on the molecular ordering and morphologies of P3HT films was investigated by UV-Vis spectroscopy, atomic force microscopy, and polarized optical microscopy. These studies reveal that the self-assembled P3HT aggregates have well-ordered nanofibrillar structures formed via [Formula: see text]–[Formula: see text] stacking. This strategy paves the way toward fabricating well-ordered polymeric structures, especially in the field of opto-electronic applications including FETs, LEDs, and lasers, where proper alignment or molecular assembly is in great demand.

scholarly journals Solvent- and Light-Sensitive AIEE-Active Azo Dye: From Spherical to 1D and 2D Assemblies

2022 ◽  
Vol 23 (2) ◽  
pp. 965
Author(s):  
Mina Han ◽  
Ikue Abe ◽  
Jihun Oh ◽  
Jaehoon Jung ◽  
Young Ji Son ◽  
...  
Keyword(s):  
Azo Dye ◽  
Organic Dyes ◽  
Solvent Polarity ◽  
Molecular Assembly ◽  
Molecular Structures ◽  
Stimuli Responsive ◽  
Solvent Vapor ◽  
Molecular Core ◽  
Self Assembled ◽  
Solvent Molecules

Fluorescent molecular assembly systems provide an exciting platform for creating stimuli-responsive nano- and microstructured materials with optical, electronic, and sensing functions. To understand the relationship between (i) the plausible molecular structures preferentially adopted depending on the solvent polarity (such as N,N-dimethylformamide [DMF], tetrahydrofuran [THF], and toluene), (ii) the resulting spectroscopic features, and (iii) self-assembled nano-, micro-, and macrostructures, we chose a sterically crowded triangular azo dye (3Bu) composed of a polar molecular core and three peripheral biphenyl wings. The chromophore changed the solution color from yellow to pink-red depending on the solvent polarity. In a yellow DMF solution, a considerable amount of the twisted azo form could be kept stable with the help of favorable intermolecular interactions with the solvent molecules. By varying the concentration of the DMF solution, the morphology of self-assembled structures was transformed from nanoparticles to micrometer-sized one-dimensional (1D) structures such as sticks and fibers. In a pink-red toluene solution, the periphery of the central ring became more planar. The resulting significant amount of the keto-hydrazone tautomer grew into micro- and millimeter-sized 1D structures. Interestingly, when THF-H2O (1:1) mixtures were stored at a low temperature, elongated fibers were stacked sideways and eventually developed into anisotropic two-dimensional (2D) sheets. Notably, subsequent exposure of visible-light-irradiated sphere samples to solvent vapor resulted in reversible fluorescence off↔on switching accompanied by morphological restoration. These findings suggest that rational selection of organic dyes, solvents, and light is important for developing reusable fluorescent materials.

Ionic self-assembly of porphyrin nanostructures on the surface of charge-altered track-etched membranes

2010 ◽  
Vol 14 (05) ◽  
pp. 446-451 ◽  
Author(s):  
Nametso Mongwaketsi ◽  
Patrick G. Ndungu ◽  
Alexander Nechaev ◽  
Malik Maaza ◽  
Raymond Sparrow
Keyword(s):  
Electron Microscopy ◽  
Self Assembly ◽  
Membrane Pore ◽  
Force Microscopy ◽  
Atomic Force ◽  
Transmission Electron ◽  
Vis Spectroscopy ◽  
Self Assembled ◽  
Track Etched Membrane ◽  
Positively Charged

Track-etched polymer membranes are typically used as templates in the synthesis of various nanowires or nanotubes arrays. The unique advantages of track-etched membranes, such as uniform pore structure, excellent porosity, easily tailored pore sizes, and a well characterized surface chemistry, may find use in self-assembly strategies where colloidal nanostructures can be tethered to a suitable substrate to produce devices of interest. Meso-tetrakis(4-phenylsulfonicacid)porphyrin dihydrochloride and Sn(IV) tetrakis(4-pyridyl)porphyrin were used to synthesize ionic self-assembled porphyrin nanorods. The track-etched membranes surface charge was changed from negative to positive using polyethyleneimine. The porphyrin nanorods were either filtered through or self-assembled onto the surface of track-etched membranes. Comparisons were made with track-etched membranes modified with, and without, polyethyleneimine. Assembly of the porphyrin nanotubes only occurred on the surface of positively charged track-etched membranes, and filtration of the porphyrin nanorods produced a mesh-like structure on the surface of the membrane irrespective of the track-etched membrane pore diameter. In each case the characteristic absorbance profiles of the porphyrin nanorods was maintained. Transmission electron microscopy, scanning electron microscopy, atomic force microscopy, and UV-vis spectroscopy were used to characterize the various systems.

scholarly journals Controlled Self-Assembly of Conjugated Polymers via a Solvent Vapor Pre-Treatment for Use in Organic Field-Effect Transistors

Polymers ◽  
2019 ◽  
Vol 11 (2) ◽  
pp. 332 ◽  
Author(s):  
Gyounglyul Jo ◽  
Jaehan Jung ◽  
Mincheol Chang
Keyword(s):  
Conjugated Polymers ◽  
Self Assembly ◽  
Field Effect ◽  
Field Effect Transistors ◽  
Grazing Incidence ◽  
Charge Carrier Mobility ◽  
Molecular Assembly ◽  
Solvent Vapor ◽  
Precise Control ◽  
Vis Spectroscopy

A facile solution-processing strategy toward well-ordered one-dimensional nanostructures of conjugated polymers via a non-solvent vapor treatment was demonstrated, which resulted in enhancements to the charge transport characteristics of the polymers. The amount of crystalline poly(3-hexylthiophene) (P3HT) nanofibers was precisely controlled by simply varying the exposure time of solutions of P3HT solutions to non-solvent vapor. The effects of non-solvent vapor exposure on the molecular ordering and morphologies of the resultant P3HT films were systematically investigated using ultraviolet-visible (UV-vis) spectroscopy, polarized optical microscopy (POM), grazing incidence X-ray diffraction (GIXRD), and atomic force microscopy (AFM). The non-solvent vapor facilitates the π–π stacking in P3HT to minimize unfavorable interactions between the poor solvent molecules and P3HT chains. P3HT films deposited from the non-solvent vapor-treated P3HT solutions exhibited an approximately 5.6-fold improvement in charge carrier mobility as compared to that of pristine P3HT films (7.8 × 10−2 cm2 V−1 s−1 vs. 1.4 × 10−2 cm2 V−1 s−1). The robust and facile strategy presented herein would be applicable in various opto-electronics applications requiring precise control of the molecular assembly, such as organic photovoltaic cells, field-effect transistors, light-emitting diodes, and sensors.

Square-grid coordination networks of (5,10,15,20-tetra-4-pyridylporphyrinato)zinc(II) in its clathrate with two guest molecules of 1,2-dichlorobenzene: supramolecular isomerism of the porphyrin self-assembly

2009 ◽  
Vol 65 (3) ◽  
pp. m139-m142 ◽  
Author(s):  
Rajesh Koner ◽  
Israel Goldberg
Keyword(s):  
Self Assembly ◽  
Metal Ion ◽  
Three Dimensional ◽  
Two Dimensional ◽  
Coordination Networks ◽  
Guest Molecules ◽  
Square Grid ◽  
Supramolecular Isomerism ◽  
Self Assembled ◽  
Solvent Molecules

The title compound, (5,10,15,20-tetra-4-pyridylporphyrinato)zinc(II) 1,2-dichlorobenzene disolvate, [Zn(C40H24N8)]·2C6H4Cl2, contains a clathrate-type structure. It is composed of two-dimensional square-grid coordination networks of the self-assembled porphyrin moiety, which are stacked one on top of the other in a parallel manner. The interporphyrin cavities of the overlapping networks combine into channel voids accommodated by the dichlorobenzene solvent. Molecules of the porphyrin complex are located on crystallographic inversion centres. The observed two-dimensional assembly mode of the porphyrin units represents a supramolecular isomer of the unique three-dimensional coordination frameworks of the same porphyrin building block observed earlier. The significance of this study lies in the discovery of an additional supramolecular isomer of the rarely observed structures of metalloporphyrins self-assembled directly into extended coordination polymers without the use of external ligand or metal ion auxiliaries.

scholarly journals Identification and nanomechanical characterization of the fundamental single-strand protofilaments of amyloid α-synuclein fibrils

2018 ◽  
Vol 115 (28) ◽  
pp. 7230-7235 ◽  
Author(s):  
Francesco Simone Ruggeri ◽  
Fabrizio Benedetti ◽  
Tuomas P. J. Knowles ◽  
Hilal A. Lashuel ◽  
Sergey Sekatskii ◽  
...  
Keyword(s):  
Single Molecule ◽  
Self Assembly ◽  
Amyloid Fibrils ◽  
Molecular Assembly ◽  
Single Strand ◽  
Force Microscopy ◽  
Atomic Force ◽  
Presynaptic Protein ◽  
Polypeptide Chains

The formation and spreading of amyloid aggregates from the presynaptic protein α-synuclein in the brain play central roles in the pathogenesis of Parkinson’s disease. Here, we use high-resolution atomic force microscopy to investigate the early oligomerization events of α-synuclein with single monomer angstrom resolution. We identify, visualize, and characterize directly the smallest elementary unit in the hierarchical assembly of amyloid fibrils, termed here single-strand protofilaments. We show that protofilaments form from the direct molecular assembly of unfolded monomeric α-synuclein polypeptide chains. To unravel protofilaments’ internal structure and elastic properties, we manipulated nanomechanically these species by atomic force spectroscopy. The single-molecule scale identification and characterization of the fundamental unit of amyloid assemblies provide insights into early events underlying their formation and shed light on opportunities for therapeutic intervention at the early stages of aberrant protein self-assembly.

Fabrication and Properties of Self-Assembled Nanosized Magnetic Particles

2001 ◽  
Vol 707 ◽  
Author(s):  
G. Salazar-Alvarez ◽  
M. Mikhailova ◽  
M. Toprak ◽  
Y. Zhang ◽  
M. Muhammed
Keyword(s):  
Self Assembly ◽  
Magnetic Particles ◽  
Average Particle Size ◽  
The Self ◽  
Average Particle ◽  
Shell Nanoparticles ◽  
Force Microscopy ◽  
Transmission Electron ◽  
Self Assembled ◽  
Core Shell Nanoparticles

ABSTRACTThe synthesis and characterisation of gold-coated cobalt nanoparticles, as well as their chemically- and magnetically-induced self-organisation have been studied. Metallic core-shell nanoparticles were prepared using two different experimental techniques: bulk reductive precipitation, with average particles size ∼15 nm, and microemulsion confining method, with average particle size of ∼6 nm. The self-assembly of prepared nanoparticles on flat substrates was achieved by derivatising the substrate and particle surfaces with bifunctional organic molecules that attaches to both particles and substrates. Examination of the self-assembled systems was carried out by a number of characterisation techniques including transmission electron microscopy (TEM), UV-visible spectrophotometry (UV-VIS), and atomic force microscopy (AFM).

scholarly journals Self-assembly and wetting properties of gold nanorod–CTAB molecules on HOPG

2019 ◽  
Vol 10 ◽  
pp. 696-705 ◽  
Author(s):  
Imtiaz Ahmad ◽  
Floor Derkink ◽  
Tim Boulogne ◽  
Pantelis Bampoulis ◽  
Harold J W Zandvliet ◽  
...  
Keyword(s):  
Self Assembly ◽  
Cetyltrimethylammonium Bromide ◽  
Pyrolytic Graphite ◽  
The Self ◽  
Gold Nanorod ◽  
Force Microscopy ◽  
Wetting Properties ◽  
Atomic Force ◽  
Highly Ordered Pyrolytic Graphite ◽  
Self Assembled

The formation of self-assembled superstructures of cetyltrimethylammonium bromide (CTAB) after drying on a nonwetting highly ordered pyrolytic graphite (HOPG) surface have been investigated using scanning electron microscopy (SEM) and atomic force microscopy (AFM). Although SEM did not reveal coverage of CTAB layers, AFM showed not only CTAB assembly, but also the dynamics of the process on the surface. The self-assembled layers of CTAB molecules on the HOPG terraces prior to nanorod deposition were shown to change the wettability of the surface, and as a result, gold nanorod deposition takes place on nonwetting HOPG terraces.

scholarly journals Self-Assembly Investigations of Sulfonated Poly(methyl methacrylate-block-styrene) Diblock Copolymer Thin Films

2019 ◽  
Vol 2019 ◽  
pp. 1-11 ◽  
Author(s):  
Claudia Piñón-Balderrama ◽  
César Leyva-Porras ◽  
Roberto Olayo-Valles ◽  
Javier Revilla-Vázquez ◽  
Ulrich S. Schubert ◽  
...  
Keyword(s):  
Thin Films ◽  
Block Copolymers ◽  
Methyl Methacrylate ◽  
Self Assembly ◽  
Volume Fraction ◽  
Degree Of Polymerization ◽  
Solvent Vapor ◽  
Poly Methyl Methacrylate ◽  
Force Microscopy ◽  
Atomic Force

Poly(methyl methacrylate-block-styrene) block copolymers (BCs) of low dispersity were selectively sulfonated on the styrenic segment. Several combinations of degree of polymerization and volume fraction of each block were investigated to access different self-assembled morphologies. Thin films of the sulfonated block copolymers were prepared by spin-coating and exposed to solvent vapor (SVA) or thermal annealing (TA) to reach equilibrium morphologies. Atomic force microscopy (AFM) was employed for characterizing the films, which exhibited a variety of nanometric equilibrium and nonequilibrium morphologies. Highly sulfonated samples revealed the formation of a honeycomb-like morphology obtained in solution rather than by the self-assembly of the BC in the solid state. The described morphologies may be employed in applications such as templates for nanomanufacturing and as cover and binder of catalytic particles in fuel cells.

Well-Ordered Self-Assembly Growth of Strain-Modulated SrTiO3 Thin Films: Templates for Complex Oxide Quantum Wires

2005 ◽  
Vol 475-479 ◽  
pp. 4255-4260 ◽  
Author(s):  
Yan Rong Li ◽  
Jin Long Li ◽  
Ying Zhang ◽  
Xin Wu Deng ◽  
Fan Yang ◽  
...  
Keyword(s):  
Compressive Stress ◽  
Self Assembly ◽  
Quantum Wires ◽  
Complex Oxide ◽  
High Energy ◽  
The Self ◽  
Ex Situ ◽  
Force Microscopy ◽  
Atomic Force ◽  
Self Assembled

Well-ordered self-assembled SrTiO3 thin film, as a template for complex oxide quantum wires, was fabricated on LaAlO3 (100) single crystal substrates with laser molecular beam epitaxy. The self-assembled growth was in-situ monitored by reflective high energy electron diffraction. The morphology evolutions of the films as a function of thickness were studied by ex-situ atomic force microscopy. As the thickness of the films increased from 3.875nm to 46.5nm gradually, the compressive stress-induced SrTiO3 films exhibited a periodic well-ordered ripple structure, which formed a unique nanoassembled template for the fabrication of quantum wires. Small angle X-ray scattering technique was employed to investigate the structure. Symmetric satellite peaks were discovered, indicating the well-ordered superstructure. In contrast, the similar superstructure was not observed during the growth of the tensile stress-induced LaAlO3 films on SrTiO3 substrates. The Compressive stress was considered as the main reason of the self-assembled growth, and systematical elucidation about strain mechanism was discussed. These results might provide an efficient method for the controllable formation of well-aligned template of quantum wire for complex oxide with desirable structure via proper modulation of strains.

Rapid dissolution of β-chitin and hierarchical self-assembly of chitin chains in aqueous KOH/urea solution

2021 ◽  
Vol 23 (8) ◽  
pp. 3048-3060
Author(s):  
Junchao Huang ◽  
Yi Zhong ◽  
Pingdong Wei ◽  
Jie Cai
Keyword(s):  
Self Assembly ◽  
Urea Solution ◽  
Rapid Dissolution ◽  
Self Assembled ◽  
Solvent Molecules

β-chitin allows for rapid penetration of solvent molecules, followed by swelling and dissolution. During neutralization, the chitin chains self-assembled into nanofibrils, and even the formation of hydrogels of crystalline α-chitin.

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