Mesoscale Block Copolymers

Self-spinning filaments for autonomously linked microfibers

Filamentous bundles are ubiquitous in Nature, achieving highly adaptive functions and structural integrity from assembly of diverse mesoscale supramolecular elements. Engineering routes to synthetic, topologically integrated analogs demands precisely coordinated control of multiple filaments' shapes and positions, a major challenge when performed without complex machinery or labor-intensive processing. Here, we demonstrate a photocreasing design that encodes local curvature and twist into mesoscale polymer filaments, enabling their programmed transformation into target 3-dimensional geometries. Importantly, patterned photocreasing of filament arrays drives autonomous spinning to form linked filament bundles that are highly entangled and structurally robust. In individual filaments, photocreases unlock paths to arbitrary, 3-dimensional curves in space. Collectively, photocrease-mediated bundling establishes a transformative paradigm enabling smart, self-assembled mesostructures that mimic performance-differentiating structures in Nature (e.g., tendon and muscle fiber) and the macro-engineered world (e.g., rope).

Helical Self-Assembly of Amphiphilic Chiral Azobenzene Alternating Copolymers

Imposing chirality to supramolecular architectures is an important step forward toward understanding and utilization of chiral nanomaterials. This article reports the self-assembly of amphiphilic chiral alternating copolymers of poly(binaphthyl azobenzene-alt-hexaethylene glycol) (P(BNPAzo-alt-EG₆)) into helical supramolecular rods. Unlike conventional chiral assembly of copolymers largely through intermolecular organization, the intrachain stacking of chiral units along the main chain into single molecular micelles with amplified axial chirality of binaphthyl is key to the formation of helical supramolecular rods, which takes advantage of the particular chiral unit and soft unit alternating topological structure of the backbones. Moreover, the supramolecular self-assembly is light reversible because the azobenzene rings in the backbone scarcely execute trans- to cis-isomerization upon UV irradiation, and therefore the supramolecular rods keep their sublevel chirality even though the helical appearance was destroyed. This work paves an effective route to construct and regulate chiral supramolecular architectures and reveals an insight into natural and artificial chiral self-assembly.

Coupled oscillation and spinning of photothermal particles in Marangoni optical traps

Cyclic actuation is critical for driving motion and transport in living systems, ranging from oscillatory motion of bacterial flagella to the rhythmic gait of terrestrial animals. These processes often rely on dynamic and responsive networks of oscillators-a regulatory control system that is challenging to replicate in synthetic active matter. Here, we describe a versatile platform of light-driven active particles with interaction geometries that can be reconfigured on demand, enabling the construction of oscillator and spinner networks. We employ optically induced Marangoni trapping of particles confined to an air-water interface and subjected to patterned illumination. Thermal interactions among multiple particles give rise to complex coupled oscillatory and rotational motions, thus opening frontiers in the design of reconfigurable, multiparticle networks exhibiting collective behavior.

Catalytic potential of cobalt oxide and agar nanocomposite hydrogel for the chemical reduction of organic pollutants

In this study, cobalt oxide nanoparticles (Co₃O₄ NPs) were synthesized by precipitation method from cobalt sulphate solution with basic pH, followed by calcination. The ex-situ synthesized Co₃O₄ NPs were mixed with hot agar (AG) aqueous solution. The preparation of AG- Co₃O₄ nanocomposite hydrogel was carried out by self-association method promoted by thermal denaturation. The quenching of hot suspension from 80 °C to room temperature resulted in the formation of AG-Co₃O₄ nanocomposite hydrogel. The as-synthesized AG-Co₃O₄ was characterized by FTIR, XRD and SEM techniques. In order to test the catalytic activity, AG-Co₃O₄ was used as a heterogeneous catalyst for the reduction of methylene blue (MB), congo red (CR) and 4-nitrophenol (4-NP). The excellent performance of the AG-Co₃O₄ was shown by the reaction rate constant (k_app) values of 0.3623, 0.2114 and 0.2893 for MB, 4-NP and CR, respectively. All these results were obtained with R² above 94 and utilization of an AG-Co₃O₄ catalyst. Furthermore, the catalytic reduction was studied with varying dye concentration and catalyst dose. This study showed that AG-Co₃O₄ catalyst has high potential for remediation of environmental pollutants in wastewaters.