Programmable colloidal molecules from sequential capillarity-assisted particle assembly

The assembly of artificial nanostructured and microstructured materials which display structures and functionalities that mimic nature’s complexity requires building blocks with specific and directional interactions, analogous to those displayed at the molecular level. Despite remarkable progress in synthesizing “patchy” particles encoding anisotropic interactions, most current methods are restricted to integrating up to two compositional patches on a single “molecule” and to objects with simple shapes. Currently, decoupling functionality and shape to achieve full compositional and geometrical programmability remains an elusive task. We use sequential capillarity-assisted particle assembly which uniquely fulfills the demands described above. This is a new method based on simple, yet essential, adaptations to the well-known capillary assembly of particles over topographical templates. Tuning the depth of the assembly sites (traps) and the surface tension of moving droplets of colloidal suspensions enables controlled stepwise filling of traps to “synthesize” colloidal molecules. After deposition and mechanical linkage, the colloidal molecules can be dispersed in a solvent. The template’s shape solely controls the molecule’s geometry, whereas the filling sequence independently determines its composition. No specific surface chemistry is required, and multifunctional molecules with organic and inorganic moieties can be fabricated. We demonstrate the “synthesis” of a library of structures, ranging from dumbbells and triangles to units resembling bar codes, block copolymers, surfactants, and three-dimensional chiral objects. The full programmability of our approach opens up new directions not only for assembling and studying complex materials with single-particle-level control but also for fabricating new microscale devices for sensing, patterning, and delivery applications.

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The rheology and microstructure of concentrated non-colloidal suspensions of deformable capsules

Journal of Fluid Mechanics ◽

10.1017/jfm.2011.307 ◽

2011 ◽

Vol 685 ◽

pp. 202-234 ◽

Cited By ~ 39

Author(s):

Jonathan R. Clausen ◽

Daniel A. Reasor ◽

Cyrus K. Aidun

Keyword(s):

Normal Stress ◽

Three Dimensional ◽

Colloidal Suspensions ◽

Elastic Membrane ◽

Normal Stresses ◽

Particle Deformation ◽

Self Diffusion ◽

Sign Change ◽

Stress Changes ◽

Particle Level

AbstractA detailed study into the rheology and microstructure of dense suspensions of initially spherical capsules is presented, where capsules are composed of a fluid-filled interior surrounded by an elastic membrane. This study couples a lattice-Boltzmann fluid solver to a finite-element membrane model creating a robust and scalable method for the simulation of these suspensions. A Lees–Edwards boundary condition is used to simulate periodic simple shear to obtain bulk rheological properties, and three-dimensional results are presented for capsules in the regime of negligible inertia, Brownian motion and colloidal interparticle forces. The simulation results focus on describing the suspension rheology as a function of the particle concentration and deformability, and relating these macroscopic rheological findings to changes at the particle level, i.e. the suspension microstructure. Several important findings are made: suspensions of deformable capsules are found to be shear thinning, and the initially compressive normal stresses associated with rigid spherical suspensions undergo rapid changes with moderate levels of particle deformation. These normal stress changes are particularly evident in the first normal stress difference, which undergoes a sign change at fairly minor levels of deformation, and the particle pressure, which decreases rapidly with increasing particle deformability. Changes in the microstructure as quantified by the single-body microstructure and the pair distribution function are reported. Also, results calculating particle self-diffusion are presented and related to changes in the normal stresses.

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Mechanically-Tunable Quantum Interference in Ferrocene-Based Single-Molecule Junctions

10.26434/chemrxiv.12252059 ◽

2020 ◽

Author(s):

María Camarasa-Gómez ◽

Daniel Hernangómez-Pérez ◽

Michael S. Inkpen ◽

Giacomo Lovat ◽

E-Dean Fung ◽

...

Keyword(s):

Single Molecule ◽

Quantum Interference ◽

Degrees Of Freedom ◽

Building Blocks ◽

Ferrocene Derivative ◽

Single Molecule Junctions ◽

Molecule Junction ◽

Single Molecule Junction ◽

The Impact ◽

D Orbitals

Ferrocenes are ubiquitous organometallic building blocks that comprise a Fe atom sandwiched between two cyclopentadienyl (Cp) rings that rotate freely at room temperature. Of widespread interest in fundamental studies and real-world applications, they have also attracted some interest as functional elements of molecular-scale devices. Here we investigate the impact of the configurational degrees of freedom of a ferrocene derivative on its single-molecule junction conductance. Measurements indicate that the conductance of the ferrocene derivative, which is suppressed by two orders of magnitude as compared to a fully conjugated analog, can be modulated by altering the junction configuration. Ab initio transport calculations show that the low conductance is a consequence of destructive quantum interference effects that arise from the hybridization of metal-based d-orbitals and the ligand-based π-system. By rotating the Cp rings, the hybridization, and thus the quantum interference, can be mechanically controlled, resulting in a conductance modulation that is seen experimentally.

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Lath Martensite Microstructure Modeling: A High-Resolution Crystal Plasticity Simulation Study

Materials ◽

10.3390/ma14030691 ◽

2021 ◽

Vol 14 (3) ◽

pp. 691

Author(s):

Francisco-José Gallardo-Basile ◽

Yannick Naunheim ◽

Franz Roters ◽

Martin Diehl

Keyword(s):

High Resolution ◽

Mechanical Behavior ◽

Crystal Plasticity ◽

Lath Martensite ◽

Three Dimensional ◽

Building Blocks ◽

Quantitative Agreement ◽

Carbon Steels ◽

Plastic Behavior ◽

Austenitic Phase

Lath martensite is a complex hierarchical compound structure that forms during rapid cooling of carbon steels from the austenitic phase. At the smallest, i.e., ‘single crystal’ scale, individual, elongated domains, form the elemental microstructural building blocks: the name-giving laths. Several laths of nearly identical crystallographic orientation are grouped together to blocks, in which–depending on the exact material characteristics–clearly distinguishable subblocks might be observed. Several blocks with the same habit plane together form a packet of which typically three to four together finally make up the former parent austenitic grain. Here, a fully parametrized approach is presented which converts an austenitic polycrystal representation into martensitic microstructures incorporating all these details. Two-dimensional (2D) and three-dimensional (3D) Representative Volume Elements (RVEs) are generated based on prior austenite microstructure reconstructed from a 2D experimental martensitic microstructure. The RVEs are used for high-resolution crystal plasticity simulations with a fast spectral method-based solver and a phenomenological constitutive description. The comparison of the results obtained from the 2D experimental microstructure and the 2D RVEs reveals a high quantitative agreement. The stress and strain distributions and their characteristics change significantly if 3D microstructures are used. Further simulations are conducted to systematically investigate the influence of microstructural parameters, such as lath aspect ratio, lath volume, subblock thickness, orientation scatter, and prior austenitic grain shape on the global and local mechanical behavior. These microstructural features happen to change the local mechanical behavior, whereas the average stress–strain response is not significantly altered. Correlations between the microstructure and the plastic behavior are established.

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Picosecond time-resolved photon antibunching measures nanoscale exciton motion and the true number of chromophores

Nature Communications ◽

10.1038/s41467-021-21474-z ◽

2021 ◽

Vol 12 (1) ◽

Author(s):

Gordon J. Hedley ◽

Tim Schröder ◽

Florian Steiner ◽

Theresa Eder ◽

Felix J. Hofmann ◽

...

Keyword(s):

Rational Design ◽

Three Dimensional ◽

Dna Origami ◽

Fluorescent Nanoparticles ◽

Time Resolved ◽

Exciton Diffusion ◽

Polymer Aggregates ◽

True Number ◽

Particle Level ◽

Photon Antibunching

AbstractThe particle-like nature of light becomes evident in the photon statistics of fluorescence from single quantum systems as photon antibunching. In multichromophoric systems, exciton diffusion and subsequent annihilation occurs. These processes also yield photon antibunching but cannot be interpreted reliably. Here we develop picosecond time-resolved antibunching to identify and decode such processes. We use this method to measure the true number of chromophores on well-defined multichromophoric DNA-origami structures, and precisely determine the distance-dependent rates of annihilation between excitons. Further, this allows us to measure exciton diffusion in mesoscopic H- and J-type conjugated-polymer aggregates. We distinguish between one-dimensional intra-chain and three-dimensional inter-chain exciton diffusion at different times after excitation and determine the disorder-dependent diffusion lengths. Our method provides a powerful lens through which excitons can be studied at the single-particle level, enabling the rational design of improved excitonic probes such as ultra-bright fluorescent nanoparticles and materials for optoelectronic devices.

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Stress-strain curve of paper revisited

Nordic Pulp & Paper Research Journal ◽

10.3183/npprj-2012-27-02-p318-328 ◽

2012 ◽

Vol 27 (2) ◽

pp. 318-328 ◽

Cited By ~ 37

Author(s):

Svetlana Borodulina ◽

Artem Kulachenko ◽

Mikael Nygårds ◽

Sylvain Galland

Keyword(s):

Three Dimensional ◽

Strain Curve ◽

Failure Behavior ◽

Three Dimensional Model ◽

Stress Strain Curve ◽

Stress Strain ◽

Fiber Network ◽

Bonding Parameters ◽

Particle Level ◽

The Impact

Abstract We have investigated a relation between micromechanical processes and the stress-strain curve of a dry fiber network during tensile loading. By using a detailed particle-level simulation tool we investigate, among other things, the impact of “non-traditional” bonding parameters, such as compliance of bonding regions, work of separation and the actual number of effective bonds. This is probably the first three-dimensional model which is capable of simulating the fracture process of paper accounting for nonlinearities at the fiber level and bond failures. The failure behavior of the network considered in the study could be changed significantly by relatively small changes in bond strength, as compared to the scatter in bonding data found in the literature. We have identified that compliance of the bonding regions has a significant impact on network strength. By comparing networks with weak and strong bonds, we concluded that large local strains are the precursors of bond failures and not the other way around.

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ChemInform Abstract: Efficient Synthetic Strategy to Construct Three-Dimensional 4f-5d Networks Using Neutral Two-Dimensional Layers as Building Blocks.

ChemInform ◽

10.1002/chin.201036013 ◽

2010 ◽

Vol 41 (36) ◽

pp. no-no

Author(s):

Hu Zhou ◽

Ai-Hua Yuan ◽

Su-Yan Qian ◽

You Song ◽

Guo-Wang Diao

Keyword(s):

Three Dimensional ◽

Building Blocks ◽

Two Dimensional ◽

Synthetic Strategy

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Design and Optimization of a Shape Memory Alloy-Based Self-Folding Sheet

Journal of Mechanical Design ◽

10.1115/1.4025382 ◽

2013 ◽

Vol 135 (11) ◽

Cited By ~ 39

Author(s):

Edwin Peraza-Hernandez ◽

Darren Hartl ◽

Edgar Galvan ◽

Richard Malak

Keyword(s):

Shape Memory Alloy ◽

Shape Memory ◽

Three Dimensional ◽

Building Blocks ◽

Passive Layer ◽

Von Mises Stress ◽

Maximum Temperature ◽

Radius Of Curvature ◽

Folding Angle ◽

The Impact

Origami engineering—the practice of creating useful three-dimensional structures through folding and fold-like operations on two-dimensional building-blocks—has the potential to impact several areas of design and manufacturing. In this article, we study a new concept for a self-folding system. It consists of an active, self-morphing laminate that includes two meshes of thermally-actuated shape memory alloy (SMA) wire separated by a compliant passive layer. The goal of this article is to analyze the folding behavior and examine key engineering tradeoffs associated with the proposed system. We consider the impact of several design variables including mesh wire thickness, mesh wire spacing, thickness of the insulating elastomer layer, and heating power. Response parameters of interest include effective folding angle, maximum von Mises stress in the SMA, maximum temperature in the SMA, maximum temperature in the elastomer, and radius of curvature at the fold line. We identify an optimized physical realization for maximizing folding capability under mechanical and thermal failure constraints. Furthermore, we conclude that the proposed self-folding system is capable of achieving folds of significant magnitude (as measured by the effective folding angle) as required to create useful 3D structures.

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A new three-dimensional anionic cadmium(II) dicyanamide network

Acta Crystallographica Section C Structural Chemistry ◽

10.1107/s2053229614022360 ◽

2014 ◽

Vol 70 (11) ◽

pp. 1054-1056 ◽

Cited By ~ 9

Author(s):

Qiang Li ◽

Hui-Ting Wang

Keyword(s):

Crystal Structure ◽

Aqueous Solution ◽

Unit Cell Volume ◽

Three Dimensional ◽

Building Blocks ◽

The Other ◽

Dimensional Structure ◽

Cadmium Nitrate ◽

Nitrate Tetrahydrate ◽

Anionic Framework

A new cadmium dicyanamide complex, poly[tetramethylphosphonium [μ-chlorido-di-μ-dicyanamido-κ4N1:N5-cadmium(II)]], [(CH3)4P][Cd(NCNCN)2Cl], was synthesized by the reaction of tetramethylphosphonium chloride, cadmium nitrate tetrahydrate and sodium dicyanamide in aqueous solution. In the crystal structure, each CdIIatom is octahedrally coordinated by four terminal N atoms from four anionic dicyanamide (dca) ligands and by two chloride ligands. The dicyanamide ligands play two different roles in the building up of the structure; one role results in the formation of [Cd(dca)Cl]2building blocks, while the other links the building blocks into a three-dimensional structure. The anionic framework exhibits a solvent-accessible void of 673.8 Å3, amounting to 47.44% of the total unit-cell volume. The cavities in the network are occupied by pairs of tetramethylphosphonium cations.

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Assembly of multicomponent structures from hundreds of micron-scale building blocks using optical tweezers

Microsystems & Nanoengineering ◽

10.1038/s41378-021-00272-z ◽

2021 ◽

Vol 7 (1) ◽

Author(s):

Jeffrey E. Melzer ◽

Euan McLeod

Keyword(s):

Optical Tweezers ◽

Three Dimensional ◽

Building Blocks ◽

Optical Tweezer ◽

Device Fabrication ◽

Positional Accuracy ◽

Component Structure ◽

Material Development ◽

Critical Process Parameters ◽

Optical Positioning

AbstractThe fabrication of three-dimensional (3D) microscale structures is critical for many applications, including strong and lightweight material development, medical device fabrication, microrobotics, and photonic applications. While 3D microfabrication has seen progress over the past decades, complex multicomponent integration with small or hierarchical feature sizes is still a challenge. In this study, an optical positioning and linking (OPAL) platform based on optical tweezers is used to precisely fabricate 3D microstructures from two types of micron-scale building blocks linked by biochemical interactions. A computer-controlled interface with rapid on-the-fly automated recalibration routines maintains accuracy even after placing many building blocks. OPAL achieves a 60-nm positional accuracy by optimizing the molecular functionalization and laser power. A two-component structure consisting of 448 1-µm building blocks is assembled, representing the largest number of building blocks used to date in 3D optical tweezer microassembly. Although optical tweezers have previously been used for microfabrication, those results were generally restricted to single-material structures composed of a relatively small number of larger-sized building blocks, with little discussion of critical process parameters. It is anticipated that OPAL will enable the assembly, augmentation, and repair of microstructures composed of specialty micro/nanomaterial building blocks to be used in new photonic, microfluidic, and biomedical devices.

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