Polymerization-Induced Hierarchical Hybrid Particles from Siloxane Emulsification Endowing Polyurethane Composite Coating with Superhydrophobicity, Thermal Insulation, and Fluorescence.

Hierarchically structural particles (HSPs) are highly regarded as favorable nanomaterials for superhydrophobic coating due to their special multiscale structure and surface physicochemical properties. However, most of the superhydrophobic coatings constructed from HSPs are monofunctional, constraining their broader applications. Moreover, traditional methods for constructing HSPs mostly rely on complicated chemical routes and template removal. Herein, we propose an innovative strategy (one-pot method) for producing multifunctional hierarchical hybrid particles (HHPs). Polysilsesquioxane (PSQ), generated from hydrolysis condensation of methyltriethoxylsilane, is used as the sole stabilizer to anchor on the surface of styrene and short fluoroalkyl compound tridecafluorooctyl acrylate comonomers droplets, forming a mesoporous PSQ shell. Subsequently, the comonomers inside of the shell perform restricted polymerization to generate the HHP due to the driving of the mesoporous capillary force. The HHP is then mixed with waterborne polyurethane (WPU) to develop a robust nanocomposite coating (WPU-HHP). Through the deliberate design of the HHP components, the WPU-HHP coating has thermal insulation, photoluminescence properties, and the ability to achieve a wettability transition during abrasion. Our research has achieved the integration of multifunctionality in one waterborne hybrid system, broadening the application areas of nanocomposite coatings.

Shape-Tunable Hollow Polysiloxane Nanoparticles Based on a Surfactant-Free Soft Templating Method and Their Application as a Drug Carrier.

A surfactant-free soft-templating method has been used to prepare polysiloxane hollow nanoparticles with a controllable shape. This method is simple and has the potential for large-scale preparation. For the first time, we successfully obtained hollow polysiloxane nanoparticles with different shapes, including eccentric hollow polysiloxane microspheres (EHPM), apple-like hollow polysiloxane microparticles (AHPM), and bowl-like hollow polysiloxane microparticles (BHPM), by simply changing the solvent. In this method, the hydrolyzed methyltriethoxysilane (MTES) not only stabilizes the system as a surfactant but also acts as a reactant for subsequent reactions, so no additional surfactant is needed. In addition, the formation mechanism of hollow polysiloxane microparticles with different shapes is also proposed: that is, MTES hydrolyzed under acidic conditions to form a surfactant, which changes the system from suspension to a stable oil-in-water emulsion. Then, under alkaline conditions, the hydrolyzed MTES polycondenses and nucleates at the oil-water interface. At the same time, with the process of polycondensation, the hydrolyzed MTES will migrate to the nucleation site driven by surface tension, thus forming an eccentric core/shell (solvent/polysiloxane) structure. Due to the different forces between hydrolyzed MTES and different solvents, the deviation degree of hollow in microspheres is different, thus forming particles with various morphologies. This synthesis method provides a new idea for the preparation of shapeable anisotropic hollow structures. Finally, we use AHPM to study the application of the drug load. The results show that the prepared hollow polysiloxane particles have a good drug loading capacity and release performance. It can be predicted that the shape-tunable hollow polysiloxane particles prepared by this method have broad application prospects in the field of drug delivery.

Surface Tension-Induced Eccentric Hollow Polysiloxane Microspheres in a Surfactant-Free System and Their Applications as a Nanoreactor and Nanomotor.

Eccentric hollow polysiloxane microspheres (EHPMs) have attracted significant attention due to their potential in energy storage, drug delivery, and heterogeneous catalysis applications. However, their preparation pathways are often particularly complex. Therefore, it is critical to find a simple method for preparing EHPMs. In this study, a surfactant-free emulsification method is proposed to prepare EHPM. Under acidic conditions, methyl triethoxysilane (MTES) is hydrolyzed at the oil-water interface, with the hydrolyzed MTES demonstrating amphiphilic properties, and it could be anchored on the xylene surface to form an oil-in-water emulsion. The solution, when adjusted to alkaline, nucleated from a point at the oil-water interface. Driven by the surface tension, the hydrolyzed MTES migrated to the nucleation site with decreasing hydrophilicity. As a result, an EHPM formed. This process provides a simple, low cost, and environmentally friendly strategy for the preparation of EHPM, which demonstrated potential in catalytic and nanomotor applications.

Ultra-sensitive amplitude engineering and sign reversal of circular dichroism in quasi-3D chiral nanostructures.

Circular dichroism (CD), as one of the most representative chiroptical effects, provides a simple strategy for the detection and characterization of the molecular chirality. The enhancement and sign reversal of CD are of great importance for its practical applications in chiral bio-sensing, chirality switching and optical filtering, etc. Here, we realize considerable adjustments and the sign reversal of CD in quasi-three-dimensional (quasi-3D) combined Archimedean spiral nanostructures. With special local and lattice configurations, the nanostructures have both right-handed and left-handed geometric chirality, which are designed based on the proximity effect of stencil lithography. We find that the CD response of the nanostructures becomes obvious once its height exceeds 200 nm and can be adjusted by the further increase of the height or the change of the blade spacing of the nanostructures. The CD reversal is achieved by utilizing the competition of two chiral centers when the height or blade spacing exceeds a critical value. Further analysis of the scattering power of multipole moments reveals that the CD modulation is determined by both magnetic dipole moment and electric quadrupole moment. Benefiting from the highly sensitive CD response to the height, the extreme sign reversal of CD is achieved when a sub-10-nm ultrathin medium layer is anchored on the surface of the nanostructures, which provides a promising strategy for ultra-sensitive chiral bio-sensing.