Nicholas A. Kotov

Self‐assembled materials with complex nanoscale and mesoscale architecture attract considerable attention in energy and sustainability technologies. Their high performance can be attributed to high surface area, quantum effects, and hierarchical organization. Delineation of these contributions is, however, difficult because complex materials display stochastic structural patterns combining both order and disorder, which is difficult to be consistently reproduced yet being important for materials' functionality. Their compositional variability make systematic studies even harder. Here, a model system of FeSe2 “hedgehog” particles (HPs) was selected  to gain insight into the mechanisms of charge storage n complex nanostructured materials common for batteries and supercapacitors. Specifically, HPs represent self‐assembled biomimetic nanomaterials with a medium level of complexity; they display an organizational …

The incessant mutations of viruses, variable immune responses, and likely emergence of new viral threats necessitate multiple approaches to novel antiviral therapeutics. Furthermore, the new antiviral agents should have broad-spectrum activity and be environmentally stable. Here, we show that biocompatible tapered CuS nanoparticles (NPs) efficiently agglutinate coronaviruses with binding affinity dependent on the chirality of surface ligands and particle shape. L-penicillamine-stabilized NPs with left-handed curved apexes display half-maximal inhibitory concentrations (IC50) as low as 0.66 pM (1.4 ng/mL) and 0.57 pM (1.2 ng/mL) for pseudo-type SARS-CoV-2 viruses and wild-type Wuhan-1 SARS-CoV-2 viruses, respectively, which are about 1,100 times lower than those for antibodies (0.73 nM). Benefiting from strong NPs–protein interactions, the same particles are also effective against other strains of …

Chiral plasmonic surfaces with 3D “forests” from nanohelicoids should provide strong optical rotation due to alignment of helical axis with propagation vector of photons. However, such three-dimensional nanostructures also demand multi-step nanofabrication, which is incompatible with many substrates. Large-scale photonic patterns on polymeric and flexible substrates remain unattainable. Here, we demonstrate the substrate-tolerant direct-write printing and patterning of silver nanohelicoids with out-of-plane 3D orientation using circularly polarized light. Centimeter-scale chiral plasmonic surfaces can be produced within minutes using inexpensive medium-power lasers. The growth of nanohelicoids is driven by the symmetry-broken site-selective deposition and self-assembly of the silver nanoparticles (NPs). The ellipticity and wavelength of the incident photons control the local handedness and size of the printed …

F28. 00008: StructuralGT v2. 0: Graph theoretic characterization and modeling of complex networked materials

Chiral halide perovskite materials promise both superior light response and the capability to distinguish circularly polarized emissions, which are especially common in the fluorescence spectra of organic chiral materials. Herein, thin-film field-effect transistors (FETs) based on chiral quasi-two-dimensional perovskites are explored, and the temperature dependence of the charge carrier transport mechanism over the broad temperature range (80–300 K) is revealed. A typical p-type charge transport behavior is observed for both left-handed (S-C6H5(CN2)2NH3)2(CH3NH3)n−1PbnI3n+1 and right-handed (R-C6H5(CN2)2NH3)2(CH3NH3)n−1PbnI3n+1 chiral perovskites, with maximum carrier mobilities of 1.7 × 10–5 cm2 V–1 s–1 and 2.5 × 10–5 cm2 V–1 s–1 at around 280 K, respectively. The shallow traps with smaller activation energy (0.03 eV) hinder the carrier transport over the lower temperature regime (80–180 …

YBNMDCCMCLUHBL-UHFFFAOYSA-N (2, 5-dioxopyrrolidin-1-yl) 4-pyren-1-ylbutanoate Chemical compound C= 1C= C (C2= C34) C= CC3= CC= CC4= CC= C2C= 1CCCC (= O) ON1C (= O) CCC1= O YBNMDCCMCLUHBL-UHFFFAOYSA-N 0.000 claims description 92

Stimuli‐responsive hydrogels are intriguing biomimetic materials. Previous efforts to develop mechano‐responsive hydrogels have mostly relied on chemical modifications of the hydrogel structures. Here, we present a simple, generalizable strategy that confers mechano‐responsive behavior on hydrogels. Our approach involves embedding hybrid vesicles, composed of phospholipids and amphiphilic block copolymers, within the hydrogel matrix to act as signal transducers. Under mechanical stress, these vesicles undergo deformation and rupture, releasing encapsulated compounds that can control the hydrogel network. To demonstrate this concept, we embedded vesicles containing ethylene glycol tetraacetic acid (EGTA), a calcium chelator, into a calcium‐crosslinked alginate hydrogel. When compressed, the released EGTA sequesters calcium ions and degrades the hydrogel. This study provides a novel …

Inorganic particles are effective photocatalysts for the liquid-state production of organic precursors and monomers at ambient conditions. However, poor colloidal stability of inorganic micro- and nanoparticles in low-polarity solvents limits their utilization as heterogeneous catalysts and coating them with surfactants drastically reduces their catalytic activity. Here we show that effective photo-oxidation of liquid cyclohexane (CH) is possible using spiky particles from metal oxides with hierarchical structure combining micro- and nanoscale structural features engineered for enhanced dispersibility in CH. Nanoscale ZnO spikes are assembled radially on α-Fe2O3 microcube cores to produce complex ‘hedgehog’ particles (HPs). The ‘halo’ of stiff spikes reduces van der Waals attraction, preventing aggregation of the catalytic particles. Photocatalysis in Pickering emulsions formed by HPs with hydrogen peroxide provides a …