Polyhedral Oligomeric Silsesquioxane (POSS) Surface Grafting: A Novel Method to Enhance Polylactide Hydrolysis Resistance

This work considers the development of an easy and scalable approach to change the features of poly(l-lactide) (PLLA) films, which is based on the application of a surface treatment with an amino-functionalized polyhedral oligomeric silsesquioxane (POSS). Indeed, the developed approach is based on the potential reactivity of POSS amino group towards the polymer functionalities to produce an aminolysis reaction, which should promote the direct grafting of the silsesquioxane molecules on the polymer surface. Neat and treated films were studied by infrared spectroscopy and X-ray photoelectron spectroscopy, which proved the effectiveness of POSS grafting. Moreover, scanning electron microscopy measurements demonstrated the homogeneous distribution of Si on the film surface treated with the silsesquioxane. The influence of the film treatment on the surface wettability was evidenced by contact angle measurements. These findings demonstrated a relevant enhancement of the surface hydrophobicity, which increase turned out to depend on the conditions applied, as it increased by increasing the reaction temperature and the contact time. Finally, in order to evaluate the stability of neat and of the treated PLLA films the surface morphology of the samples treated with pH 7.4 buffer at 50 °C was studied.

Lanthanide complex-functionalized polyhedral oligomeric silsesquioxane with multicolor emission covered from 450 nm to 1700 nm

Six new hybrid materials covalently linking ternary lanthanide complexes to POSS were prepared, and the luminescent properties were investigated in detail.

Fluorescent porous film modified polymer optical fiber via "click" chemistry: stable dye dispersion and trace explosive detection

In this paper, we report a facile strategy to fabricate fluorescent porous thin film on the surface of U-bent poly(methyl methacrylate) optical fiber (U-bent POF) in situ via "click" polymerization for vapor phase sensing of explosives. Upon irradiation of evanescent UV light transmitting within the fiber under ambient condition, a porous film (POSS-thiol cross-linking film, PTCF) is synthesized on the side surface of the fiber by a thiol-ene "click" reaction of vinyl-functionalized polyhedral oligomeric silsesquioxanes (POSS-V8) and alkane dithiols. When vinyl-functionalized porphyrin, containing four allyl substituents at the periphery, is added into precursors for the polymerization, fluorescence porphyrin can be covalently bonded into the cross-linked network of PTCF. This "fastened" way reduces the aggregation-induced fluorescence self-quenching of porphyrin and enhances the physicochemical stability of the porous film on the surface of U-bent POF. Fluorescent signals of the PTCF/U-bent POF probe made by this method exhibit high fluorescence quenching toward trace TNT and DNT vapor and the highest fluorescence quenching efficiency is observed for 1, 6-hexanedimercaptan-based film. In addition, because of the presence of POSS-V8 with multi cross-linkable groups, PTCF exhibits well-organized pore network and stable dye dispersion, which not only causes fast and sensitive fluorescence quenching against vapors of nitroaromatic compounds, but also provides a repeatability of the probing performance.

POSS-tethered fluorinated diblock copolymers with linear- and star-shaped topologies: synthesis, self-assembled films and hydrophobic applications

Polyhedral oligomeric silsesquioxane (POSS) tethered fluorinated diblock copolymers are synthesized using octakis(dibromoethyl)POSS and aminopropylisobutyl POSS initiation of methylmethacrylate and dodecafluoroheptylmethacrylate.

Star-shaped POSS diblock copolymers and their self-assembled films

This first example of 16-arm, star-shaped diblock copolymers s-POSS-PMMA_277.3-b-P(MA-POSS)_{5.8,16.4,25.4} can be used as solvent-dependent coatings.

On a novel catalytic system based on electrospun nanofibers and M-POSS

We report on a novel catalytic system based on electrospun polymer nanofibers, which were modified with a metal-containing polyhedral oligomeric silsesquioxanes (M-POSS). In particular, a titanium-based POSS, characterized by an amino group as reactive side, was contacted with poly(styrene-co-maleic anhydride) (PSMA) nanofibers, which were dispersed in a solvent capable of solubilizing the above metal silsesquioxane. FTIR measurements evidenced the occurrence of the reaction between the MA group of PSMA and the amino group of POSS molecule. The catalytic activity of the PSMA/Ti-POSS-NH(2) system was proved in the degradation of sulforhodamine B under UV light. The presence of metal center, directly attached to the nanofiber surface, renders the system catalytically active.