A Robust Oil-in-Oil Emulsion for the Nonaqueous Encapsulation of Hydrophilic Payloads

Compartmentalized structures widely exist in cellular systems (organelles) and perform essential functions in smart composite materials (microcapsules, vasculatures, and micelles) to provide localized functionality and enhance materials’ compatibility. An entirely water-free compartmentalization system is of significant value to the materials community as nonaqueous conditions are critical to packaging microcapsules with water-free hydrophilic payloads while avoiding energy-intensive drying steps. Few nonaqueous encapsulation techniques are known, especially when considering just the scalable processes that operate in batch mode. Herein, we report a robust oil-in-oil Pickering emulsion system that is compatible with nonaqueous interfacial reactions as required for encapsulation of hydrophilic payloads. A major conceptual advance of this work is the notion of the partitioning inhibitora chemical agent that greatly reduces the payload’s distribution between the emulsion’s two phases, thus providing appropriate conditions for emulsion-templated interfacial polymerization. As a specific example, an immiscible hydrocarbon–amine pair of liquids is emulsified by the incorporation of guanidinium chloride (GuHCl) as a partitioning inhibitor into the dispersed phase. Polyisobutylene (PIB) is added into the continuous phase as a viscosity modifier for suitable modification of interfacial polymerization kinetics. The combination of GuHCl and PIB is necessary to yield a robust emulsion with stable morphology for 3 weeks. Shell wall formation was accomplished by interfacial polymerization of isocyanates delivered through the continuous phase and polyamines from the droplet core. Diethylenetriamine (DETA)-loaded microcapsules were isolated in good yield, exhibiting high thermal and chemical stabilities with extended shelf-lives even when dispersed into a reactive epoxy resin. The polyamine phase is compatible with a variety of basic and hydrophilic actives, suggesting that this encapsulation technology is applicable to other hydrophilic payloads such as polyols, aromatic amines, and aromatic heterocyclic bases. Such payloads are important for the development of extended pot or shelf life systems and responsive coatings that report, protect, modify, and heal themselves without intervention

Long-Range Chirality Transfer in Free Radical Polymerization of Bulky Vinyl Monomers Containing Laterally Attached <i>p</i>-Terphenyl Groups

Two series of chiral bulky vinyl monomers, 2-(4′-hexyloxyphenyl)-5-(4′-alkoxycarbonylphenyl)styrene and 2-(4′-alkoxycarbonylphenyl)-5-(4′-hexyloxyphenyl)styrene (abbreviated as S-(+)-HexMm/R-(−)-HexM0 and S-(+)-MmHex/R-(−)-M0Hex (m = 0, 1, 2, 3), respectively), were designed and synthesized. The former differed the latter only by the relative location of vinyl group, i.e., orientation against or toward the stereocenter. Except for S-(+)-HexM1 and S-(+)-HexM3, all the monomers readily underwent radical polymerization to yield the polymers displaying optical rotations and Cotton effects in the UV−vis absorption region of side groups distinct to the corresponding model compounds and mononmers, implying the formation of main chain chirality, most probable helicity. The influences of the configuration, the distance to p-terphenyl, and the position relative to vinyl group of stereocenter on the chiroptical properties of the resultant polymers were systematically studied. It was found that inverting the absolute spatial configuration of asymmetric center or changing the parity of methylene number between stereocenter and p-terphenyl alternated the direction of optical rotation of polymer, similar to the odd−even alternation behavior observed in the cholesteric phase of achiral 2,5-bis(4′-hexyloxyphenyl)styrene doped with the corresponding monomers. This parallel indicated an identical driving force for the formation of chiral mesophase and the asymmetric secondary structure of the polymer. When the spatial configuration of stereocenter was fixed, its distance to p-terphenyl rather than vinyl group played a dominant role in the induction of an excess helical sense. However, the stereogenic center at the ortho position of vinyl group exhibited a larger induction power than those at the meta position

Probing a Hidden World of Molecular Self-Assembly: Concentration-Dependent, Three-Dimensional Supramolecular Interconversions

A terpyridine-based, concentration-dependent, facile self-assembly process is reported, resulting in two three-dimensional metallosupramolecular architectures, a bis-rhombus and a tetrahedron, which are formed using a two-dimensional, planar, tris-terpyridine ligand. The interconversion between these two structures is concentration-dependent: at a concentration higher than 12 mg mL^–1, only a bis-rhombus, composed of eight ligands and 12 Cd²⁺ ions, is formed; whereas a self-assembled tetrahedron, composed of four ligands and six Cd²⁺ ions, appears upon sufficient dilution of the tris-terpyridine-metal solution. At concentrations less than 0.5 mg mL^–1, only the tetrahedron possessing an <i>S</i>₄ symmetry axis is detected; upon attempted isolation, it quantitatively reverts to the bis-rhombus. This observation opens an unexpected door to unusual chemical pathways under high dilution conditions

Stoichiometric Self-Assembly of Shape-Persistent 2D Complexes: A Facile Route to a Symmetric Supramacromolecular Spoked Wheel

An approach to multicomponent coordination-driven self-assembly of the first terpyridine-based, shape-persistent, giant two-dimensional D6h supramacromolecular spoked wheel is reported. Mixing core T6, rim T3, and ZnII or CdII ions in a stoichiometric ratio (1:6:12) permitted the selective generation of a highly symmetric spoked wheel in 94% isolated yield via geometric and thermodynamic control. The products were characterized by a combination of traveling-wave ion mobility mass spectrometry and NMR techniques together with TEM imaging, which agreed with computational simulations

Conductive Water/Alcohol-Soluble Neutral Fullerene Derivative as an Interfacial Layer for Inverted Polymer Solar Cells with High Efficiency

Dipole induced vacuum level shift has been demonstrated to be responsible for the enhanced efficiency in polymer solar cells (PSCs).The modified energy level alignment could reduce the energy barrier and facilitate charge transport, thereby increasing the efficiency of PSCs. Herein, we report a new mechanism toward enhanced efficiency by using a nondipolar water/alcohol-soluble neutral fullerene derivative to reengineer the surface of the zinc oxide (ZnO) electron extraction layer (EEL) in inverted PSCs. Because of the neutral property (ion-free) of the fullerene derivatives, no dipole moment was introduced at the EEL/active layer interface. A negligible change in open-circuit voltage was observed from inverted PSCs with the neutral fullerene derivative layer. The neutral fullerene derivative layer greatly increased the surface electronic conductivity of the ZnO EEL, suppressed surface charge recombination, and increased the short-circuit current density and fill factor. An overall power conversion efficiency increase of more than 30% from inverted PSCs was obtained. These results demonstrate that the surface electronic conductivity of the EEL plays an important role in high performance inverted PSCs

Force-Induced Near-Infrared Chromism of Mechanophore-Linked Polymers

A near-infrared (NIR) mechanophore was developed and incorporated into a poly­(methyl acrylate) chain to showcase the first force-induced NIR chromism in polymeric materials. This mechanophore, based on benzo­[1,3]­oxazine (OX) fused with a heptamethine cyanine moiety, exhibited NIR mechanochromism in solution, thin-film, and bulk states. The mechanochemical activity was validated using UV–vis–NIR absorption/fluorescence spectroscopies, gel permeation chromatography (GPC), NMR, and DFT simulations. Our work demonstrates that NIR mechanochromic polymers have considerable potential in mechanical force sensing, damage detection, bioimaging, and biomechanics

Construction of a Highly Symmetric Nanosphere via a One-Pot Reaction of a Tristerpyridine Ligand with Ru(II)

A three-dimensional, highly symmetric, terpyridine-based, spherical complex was synthesized via the coordination of four novel, trisdentate ligands and six Ru²⁺ ions, and it exhibits excellent stability over a wide range of pH values (1–14). Structural confirmation was obtained by NMR and ESI-TWIM-MS