Preparation and Properties of Benzylsulfonyl-Containing Silicone Copolymers via Ring-opening Copolymerization of Macroheterocyclosiloxane and Cyclosiloxane.

Ring-opening copolymerization (ROCP) of benzylsulfonyl macroheterocyclosiloxane (BSM) and five different cyclosiloxanes was systematically investigated. A general approach for the synthesis of benzylsulfonyl-containing silicone copolymers with various substituents, including methyl, vinyl, ethyl, and phenyl, was developed herein. A series of copolymers with variable incorporation (from 6 % to 82 %) of BSM were obtained by modifying the comonomer feed ratio and using KOH as the catalyst in a mixed solvent of dimethylformamide and toluene. The obtained copolymers exhibited various composition-dependent properties and unique viscoelasticity. Notably, the surface and fluorescent characteristics as well as the glass transition temperatures of the copolymers could be tailored by varying the amount of BSM. Unlike typical sulfone-containing polymers, such as poly(olefin sulfone)s, the prepared copolymers displayed excellent thermal and hydrolytic stability. The universal strategy developed in the present study provides a platform for the design of innovative silicone copolymers with adjustable structures and performance.

A Super-Amphiphilic 3D Silicone Sponge with High Porosity for the Efficient Adsorption of Various Pollutants.

Silicone sponge, which is nontoxic, highly flexible, insulated, and chemically inert, has great promise in the aerospace, electronics, and health care industries. However, the inherent surface properties and the harsh synthesis method limit its application. A super-amphiphilic 3D silicone sponge is designed by a thiol-ene click reaction for the first time. The sponge possesses high porosity, low density, excellent adsorption ability, and reusability for water, oil, emulsions, and Hg2+ or dyes or suspended solids in them. The sponge can selectively adsorb a very high amount (941.3 mg g-1 ) of Hg2+ from solutions (water, oil, emulsions) containing various ions at a nearly 100% removal efficiency. Cation dyes can also be selectively captured by the sponge. Furthermore, the sponge is designed as a filter element for a filtration system, and the content of the pollutants in the filtrate reaches drinkable levels after the Hg2+ and dye solutions are processed. The filter can be reused with almost unchanged filtration efficiency after a simple washing process. The successful treatment of actual/artificial polluted water proves its practical value.

Luminescent and Robust Perovskite-Silicone Elastomers Prepared by Light Induced Thiol-Ene Reaction.

The preparation of a series of luminescent perovskite-silicone elastomer (PSE) composites by embedding inorganic lead halide perovskite nanocrystals (CsPbBr3 NCs) into networks constructed by trimethylolpropane tris(2-mercaptoacetate) and sulfone-containing silicone copolymers with vinyl side groups (PSMVS) is reported herein. The networks are obtained by an environmentally friendly thiol-ene cross-linking reaction under 30 W household LED light. The conducted analysis shows that the prepared PSEs display strong green fluorescence due to encapsulation of CsPbBr3 NCs, which constitute a luminescent center in sulfone-containing silicone networks. Using PSMVS as basic polymers instead of commercial polysiloxanes endows PSEs with enhanced mechanical strength and excellent luminescent stability at high temperatures. The PSEs show robust tensile stress and >650% elongation. Additionally, the construction of colorful ultraviolet light-emitting diodes (UV-LEDs) by an in situ cross-linking process is described.

Impact of Molecular Architecture on Surface Properties and Aqueous Stabilities of Silicone-Based Carboxylate Surfactants.

Silicone surfactants consist of siloxane or carbosilane hydrophobic groups that possess better surface activity compared with alkane surfactants. The surfactants, containing Si atoms which bring excellent bond flexibility and low cohesive energy properties are a promising class of materials for unique surface working, but there are few studies to elaborate their surface activity mechanism with regard to the molecular architecture. Herein, two novel carboxylate surfactants with different silicone hydrophobic groups (Si-O-Si and Si-C-Si) were synthesized and their surface activities, aggregate behaviors, and solution stabilities were systematically investigated. Results showed that both surfactants had excellent surface activities which are attributed to the hydrophobic structure of silicone. The hydrolysis resistance of the carbosilane-based carboxylate surfactant was better than that of the siloxane-based carboxylate surfactant. The differences in hydrolysis processes for the surfactants were confirmed by the mass spectrum and kinetic analysis. Meanwhile, the aggregation number of Si-C-Si surfactants was also determined by the fluorescence quenching method for the first time.

Synthesis and Solution Behavior of Sulfonate-Based Silicone Surfactants with Specific, Atomically Defined Hydrophobic Tails.

A series of sulfonate-based silicone surfactants with different hydrophobic groups were synthesized. Two synthetic strategies are introduced to permit exquisite control over the hydrophobic moieties. Solution behavior of these surfactants was investigated by surface tensiometry, electrical conductivity, transmission electron microscopy, and dynamic light scattering. The results indicate that the aqueous behavior of the surfactants was distinctly influenced by the hydrophobic groups. Subtle distinctions in surfactant-related properties, which can be attributed to the three-dimensional molecular structures of the surfactants, can be seen for compounds with different hydrophobic moieties. Contact angle results of these surfactants indicate that they have super dispersal ability with the potential value in agriculture.

Synthesis, Properties, and Aggregation Behavior of Tetrasiloxane-Based Anionic Surfactants.

Three silicone surfactants, 3-tris(trimethylsiloxy)silylpropyl sulfonate with different alkaline counterions (lithium, sodium, and potassium), were synthesized for the first time. Their chemical structures were confirmed by FT-IR spectra, 1H NMR, and ESI-MS, and their behaviors in aqueous solutions were investigated by surface tensiometry, electrical conductivity, dynamic light scattering, and different transmission electron microscopy techniques. These anionic silicone surfactants exhibited remarkable surface activity and could reduce the surface tension of water to as low as 19.8 mN/m at the critical aggregate concentration (CAC). The adsorption and aggregation behaviors of these surfactants were assessed by determining the adsorption efficiency, minimum average area per surfactant molecule, and thermodynamic parameters. The cryo-TEM results verified that these molecules could form vesicles in water above the CAC. Moreover, the lowest surface tension, the smallest CAC value, and the largest aggregate size have been reached with potassium counterions. Thus, the different behavior of these surfactants in water can be explained by the different sizes of the hydrated ions.