A novel protocol for the preparation of uniform polymer microspheres with high yields through step polymerization of isophorone diisocyanate

Preparation of fluorescent polyurethane microspheres and their applications as reusable sensor for 4-nitrophenol detection and as microplastics model for visualizing polyurethane in cells and zebrafish

Fluorescent microspheres are of significant interests due to their wide applications in biotechnology fields. However, their preparation presents several challenges, such as the need for dye labeling, the complexity of materials and often sophisticated preparation conditions. Here a simple process for hydrophilic and crosslinked polyurethane (CPU) microspheres, with carboxyl groups on the surface via one-step precipitation polymerization in 40 min, is presented. The microsphere size is easily adjusted by varying experimental conditions. CPU microspheres exhibit high thermal and pH stability with good redispersibility in water, and emit fluorescence without any modification or dye labeling. The emission mechanism is discussed. CPU microspheres are used as fluorescent probe to detect 4-nitrophenol (4-NP) based on their emission in UV light region, with excellent selectivity and sensitivity. In addition, they are reusable with detection limit unchanged after 7 cycles of reuses, a significant feature of this work. The mechanism of fluorescence detection is thoroughly explored and ascribed to the internal filtration effect. Based on the emission in visible light region, CPU microspheres are used as a model of PU microplastics (MPs) to visualize their biodistribution in HeLa and macrophage cells, as well as in zebrafish larvae, providing a reliable tracer for the visualization and tracking of PU MPs in organisms.

Facile Preparation of Raspberry-Like SiO2@Polyurea Microspheres with Tunable Wettability and Their Application for Oil-Water Separation

Raspberry-like microspheres have been widely used as superhydrophobic materials, photonic crystals, drug carriers, etc. Nevertheless, their preparation methods, usually consisting of multiple steps, are generally time- and energy-consuming. Herein raspberry-like SiO2@polyurea microspheres (SiO2@PUM) are readily prepared via a one-step precipitation polymerization of isophorone diisocyanate in a H2O/acetone mixture with the presence of SiO2 particles. The sphere size, surface roughness, and SiO2 content of SiO2@PUM are easily adjustable by varying the experimental conditions. TEM and SEM observations reveal that the final SiO2@PUM exhibits a core-shell structure, with polyurea (PU) in the core and SiO2 particles as the shell. In the process, the SiO2 particles were initially located on the PUM surface as a monolayer. With the reaction proceeding, the monolayer of SiO2 particles became thicker, forming a thicker layer of SiO2 particles on PUM due to the accumulation of SiO2 particles, leading to a multilayer structure of SiO2 particles on the shell of SiO2@PUM. The formation mechanism of the raspberry-like SiO2@PUM was thoroughly discussed and ascribed to electrostatic attraction between the positively charged PU and negatively charged SiO2 particles. Once dried, SiO2@PUM was superhydrophobic and turned hydrophilic if water-wetted. Using a layer of SiO2@PUM, effective separation with good reusability for a variety of oil-water mixtures was achieved regardless of the oil density and types of oil-water emulsions. This work presents a novel protocol for the preparation of raspberry-like microspheres with tunable wettability via a rapid and green process, and the resulting microspheres are highly effective for the separation of diverse types of oil-water mixtures.

Robust superhydrophobic polyurea@cellulose nanocrystal coating

A multifunctional superhydrophobic PU@CNC composite coating with self-cleaning properties and mechanical durability was fabricated using a facile spraying method.

Preparation of crosslinked porous polyurea microspheres in one-step precipitation polymerization and its application for water treatment

Porous polyurea microspheres (PPUMs) were simply prepared in one-step by the precipitation polymerization of isophorone diisocyanate with triethylenetetramine and SiO₂ particles.

A facile pathway to polyurea nanofiber fabrication and polymer morphology control in copolymerization of oxydianiline and toluene diisocyanate in acetone

Polyurea nanofibers, of high thermal stability and solvent resistance, were obtained through simple precipitation polymerization of TDI and ODA in acetone at 30 °C.

Preparation of uniform poly(urea–siloxane) microspheres through precipitation polymerization

Preparation of PUSs through precipitation polymerization.

Preparation of highly uniform and crosslinked polyurea microspheres through precipitation copolymerization and their property and structure characterization

Highly uniform polyurea microspheres are prepared with tunable crosslinking through precipitation polymerization of IPDI with diethylenetriamine (DETA) in water–acetone binary solvent.

One step preparation of porous polyurea by reaction of toluene diisocyanate with water and its characterization

Porous polyurea is synthesized by reacting toluene diisocyanate with water in a water–acetone binary solvent. Materials characterization led to the likely conformations of the polymer chains owing to presence of intensive H-bonding.