Versatile Construction of Single-Tailed Giant Surfactants with Hydrophobic Poly(ε-caprolactone) Tail and Hydrophilic POSS Head

Hydrophobic cotton fabric with 3-mercaptopropyltriethoxysilane/polyhedral oligomeric silsesquioxane/1-octadecanethiol modification for oil/water separation

A protocol to produce a silsesquioxane (POSS) with a long alkyl chain coating on natural cotton (CT) fabric is applied. The surface hydroxyl groups of cotton fabric are converted with 3-mercaptopropyltriethoxysilane (MPTES) to thiol groups. Then the POSS links to the thiol groups by thiol-ene click reactions triggered by UV irradiation to produce POSS-CT or grafted with 1-octadecanethiol (ODT) using one-pot or two-pot modification protocols to generate the ODT-POSS-CT fabrics. The POSS-CT is highly hydrophobic, could absorb 0.96 g hexane/g fabrics when competing with invaded water, and reach 1.12 hexane g/g fabrics when water was absorbed separately. The one-pot modification protocol yielded surfaces with almost constant water contact angle (144o) and perfect wetting by diiodomethane (0o), producing constant dispersive component (50.8 mJ/m2) and polar component (13.6 mJ/m2). The ODT-POSS-CT via two-pot modification leads to water contact angles >143o and diiodomethane contact angle of about 46o, with corresponding dispersive and polar components being 36.1 mJ/m2 and 9.4 mJ/m2, respectively. The complete grafting of ODT onto POSS yields a compact hydrophobic layer with reduced effective surface area for dispersive components, transferring the surface from hydrophobic to omniphobic for both water and diiodomethane.

The Use of the Thiol-Ene Addition Click Reaction in the Chemistry of Organosilicon Compounds: An Alternative or a Supplement to the Classical Hydrosilylation?

This review presents the main achievements in the use of the thiol-ene reaction in the chemistry of silicones. Works are considered, starting from monomers and ending with materials.The main advantages and disadvantages of this reaction are demonstrated using various examples. A critical analysis of the use of this reaction is made in comparison with the hydrosilylation reaction.

Silsesquioxane Derivatives as Functional Additives for Preparation of Polyethylene-Based Composites: A Case of Trisilanol Melt-Condensation

In this work, polyethylene (PE) composites were prepared with a series of completely condensed silsesquioxanes (SSQ), as well as with open-cage hepta(isobutyl)trisilanol silsesquioxane. The effect of the additives on the thermal, mechanical, rheological, and crystalline properties of the composites obtained was determined. The dispersion of trisilanol derivative within polymer matrix was slightly better than that of the other isobutyl compounds, suggesting condensation of the additive to less polar products of different structure, which was confirmed by thermogravimetry (TG) and matrix-assisted laser desorption-ionization time-of-flight (MALDI-TOF) mass spectrometry analysis. The additives improved the thermal stability of polyethylene and formed composites of higher rigidity than the neat polyolefin. The results were compared to the literature data, with aminopropylhepta(isobutyl)silsesquioxane and vinylhepta(isobutyl)silsesquioxane being used partially as references, as PE composites thereof were reported earlier, but lacked some analytical results and required further investigation. It was proven that the practical upper loading limit for such silsesquioxane compounds as processing and functional additives for polyethylene should be fixed at around 1%.

Fabrication of Customized Nanogel Carriers From a UV-Triggered Dynamic Self-Assembly Strategy

Recent advances in self-assembled nanogel carriers have allowed precise design of hierarchical structures by a low-cost solution-phase approach. Typically, photochemical strategy on the tailor of morphology and dimension has emerged as a powerful tool, because light-trigger has exceptional advantages of an instant "on/off" function and spatiotemporal precision at arbitrary time. Herein, we report a tunable manipulation of sequentially morphological transition via a "living" thiol-disulfide exchange reaction from a UV-tailored hierarchical self-assembly strategy. By varying the irradiation time, the photochemical method can easily fabricate and guide a series of attractively architectural evolution in dilute aqueous solutions, by which the improving hydrophobicity and sensitive redox-responsiveness endowed these disulfide-linked nanoparticles with remarkable capacities of abundant encapsulation, effective separation, and controlled release of hydrophobic cargoes. Notably, once the exchange reaction is suspended at any point of time by removing the UV lamp, these active sites within the nanogel carriers are instantaneous deactivated and the correspondingly structural transformations are also not conducted any more. However, if the stable inert sites are reactivated as needed by turning on the UV light, the interrupting morphology evolution can continue its previous steps, which may provide a simple and novel approach to fabricating the desired self-assemblies in solutions. With regard to this advanced functionality, various nanogel carriers with customizable structures and properties have been yielded and screened for cancer therapy. Thus, this "living" controlled self-assembled method to program morphology evolution in situ is a universal strategy that will pave novel pathways for creating sequential shape-shifting and size-growing nanostructures and constructing uniform nanoscopic functional entities for advanced bio-applications.

Effect of Alkyl Chain Length in POSS Nanocage on Non-Isothermal Crystallization Behavior of PCL/Amino-POSS Nanocomposites

The study of the non-isothermal crystallization behavior of polymers is of great importance due to the effect of degree of crystallinity and crystallization process on the polymer properties. The effect of aminopropylisobutyl polyhedral oligomeric silsesquioxane (APIBPOSS) and aminopropylisooctyl polyhedral oligomeric silsesquioxane (APIOPOSS) on poly(ε-caprolactone) (PCL) crystallization is studied by differential scanning calorimetry (DSC) under non-isothermal conditions and polarized optical microscopy (POM). The crystallization kinetics is analyzed using the Avrami and Mo models, and effective activation energies are evaluated by the Friedman isoconversional method. The results show that the compatibility between polyhedral oligomeric silsesquioxanes (POSS) and PCL and POSS loading affect the crystallization process. A higher crystallization temperature, a narrower size distribution of crystallite, and a faster crystallization rate are obtained in the presence of all the studied contents of APIBPOSS and at lower contents of APIOPOSS. At APIOPOSS contents higher than 2 wt %, the crystallization temperature is lowered, the size distribution of crystallite is broadened, and the crystallization process is retarded. The presence of POSS leads to an increase in the number of nucleation sites, and a reduction in the size of the crystallite and the overall degree of crystallinity, as a result of the confinement of PCL chains caused by POSS nanoparticles.