Evaporation-driven particle self-assembly can be used to generate three-dimensional microstructures. We present a unique method to create colloidal microstructures in which we can control the amount of particles and their packing fraction. To this end, we evaporate colloidal dispersion droplets on a special type of superhydrophobic microstructured surface, on which the droplet remains in Cassie-Baxter state during the entire evaporative process. The remainders of the droplet consist of a massive spherical cluster of the microspheres, with diameters ranging from a few tens up to several hundreds of microns. We present scaling arguments to show how the final particle packing fraction of these balls depends on the dynamics of the droplet evaporation, particle size, and number of particles in the system.
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http://dx.doi.org/10.1073/pnas.1209553109 | DOI Listing |
Adv Sci (Weinh)
January 2025
Department of Chemical and Biomolecular Engineering, Korea Advanced Institute of Science and Technology (KAIST), Daejeon, 34141, Republic of Korea.
Non-close-packed crystalline arrays of colloidal particles in an elastic matrix exhibit mechanochromism. However, small interparticle distances often limit the range of reversible color shifts and reduce reflectivity during a blueshift. A straightforward, reproducible strategy using matrix swelling to increase interparticle distance and improve mechanochromic performance is presented.
View Article and Find Full Text PDFNat Commun
January 2025
College of Chemistry, Beijing Normal University, Beijing, 100875, P.R. China.
Developing donor-acceptor [n]cycloparaphenylenes (D-A [n]CPPs) with multiple emissions from different emissive states remains challenging yet crucial for achieving white-light emission in single-molecule. Here, we report our explorations into acceptor engineering of quinone-based D-A [10]CPPs (Nq/Aq/Tq[10]CPPs) via a post-lateral annulation using Diels-Alder reactions of oxTh[10]CPP. X-ray analysis reveals that Nq[10]CPP displays a side by side packing via naphthoquione stacking while Aq[10]CPP adopts an intercalated conformation through anthraquinone interaction.
View Article and Find Full Text PDFPolymers (Basel)
December 2024
Positron Group "Prof. Alfredo Dupasquier", Faculty of Exact Sciences, Tandil Institute of Materials Physics (IFIMAT), National University of the Center of the Buenos Aires Province (UNCPBA), Pinto 399, 7000 Tandil, Argentina.
The sensitivity of positron annihilation characteristics to changes in the molecular packing in network-forming polymers has been demonstrated since the early 1980s. Positron annihilation lifetime spectroscopy (PALS) is a unique technique that can provide direct information on the free volume in polymers through the experimental parameters of the free volume hole distribution, their mean value, and volume fraction. This knowledge is currently applied for PALS investigations on the main processes that govern the molecular organization in some green polymers when subjected to different synthesis procedures or environmental conditions (humidity, physical aging, temperature).
View Article and Find Full Text PDFMaterials (Basel)
December 2024
Institute of Systems Engineering, China Academy of Engineering Physics, Mianyang 621999, China.
The effects of aging treatment and the volume fraction of precipitation particles on the nano-hardness and nano-indentation morphology of Ni-based single crystal superalloys are systematically investigated. Using nano-indentation tests and atomic force microscopy (AFM), this study examined the mechanical properties and related physical mechanisms of Ni-based superalloys that have two volume fractions of precipitation particles and four aging treatment times. Results analyzed using the Oliver-Pharr method indicate that prolonging the aging time or increasing the volume fraction of particles enhances the nano-hardness and creep resistance of Ni-based single crystal superalloys and reduces the indentation-affected area.
View Article and Find Full Text PDFJ Chem Phys
January 2025
Centre for Theoretical Chemistry and Physics, The New Zealand Institute for Advanced Study (NZIAS), Massey University Albany, Private Bag 102904, Auckland 0745, New Zealand.
The theory of periodic Barlow multi-lattices (X1X2…XN)∞ with Xi ∈ {A, B, C} and Xi ≠ Xi+1 of stacked two-dimensional hexagonal close-packed layers is presented and used to derive exact lattice sum expressions in terms of fast converging Bessel function expansions for inverse power potentials. We describe in detail the mathematical properties of Barlow sphere packings and demonstrate that only two basic lattice sums are required to describe all periodic packings. For the sticky hard-sphere model with an attractive inverse power law potential, we find a linear correlation between the cohesive energies of different Barlow packings and the face-centered cubic packing fraction.
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