UV-Resistant Trifluoropropyl-Substituted Open-Cage Silsesquioxane-Pendant Polysiloxanes

Abstract

We prepared three types of tris(dimethoxysilyl)-heptatrifluoropropyl-substituted open-cage silsesquioxanes, namely hepta (3,3,3trifluoropropyl)-substituted open-cage silsesquioxanes (IC-POSSs) attached to three dimethoxysilyl groups by linkers of variable lengths at the opening vertex (TFP-Hdi, TFP-Vdi, and TFP-Adi). The dimethoxysilyl groups allowed subsequent hydrolysis and polycondensation under mild conditions to form flexible siloxane bonds. The structures of the resulting trifluoropropyl-substituted open-cage silsesquioxane-pendant polysiloxanes (P-H, P-V, and P-A) could be tuned by polycondensation temperature and the linker lengths of the tris(dimethoxysilyl)-heptatrifluoropropyl-substituted open-cage silsesquioxanes. The hybrid structure of the trifluoropropyl-substituted open-cage silsesquioxane-pendant polysiloxanes exhibited a low glass transition temperature, good thermal stability, hydrophobicity, optical transparency, and ultraviolet (UV) resistance. In particular, the transmittance of P-H exhibited no significant changes even after 11 days of UV irradiation with an average transmittance of >90% (250−600 nm). On the other hand, the transmittance of sulfur-containing P-V and P-A initially decreased after 2 days of irradiation due to oxidation of sulfur atoms to sulfoxide. Sulfoxide presence was then validated by XPS measurements. However, the transmittance remained largely unchanged during further consistent irradiation, indicating no further changes.

Ternary Siloxane Copolymers Based Tough Elastomer under Ultralow Temperatures Condition

“…With the continuous exploration of the Earth and extraterrestrial space, human beings are exposed to increasingly extreme environments, among which ultralow temperature conditions are one of the main challenges. − Silicone elastomers, characterized by exceptional resistance to high and low temperatures, − radiation, , and ultraviolet light, , as well as insulation, − air permeability, , and physiological inertness − properties, find widespread application in various fields, including electronic/electrical, aerospace, petrochemical, construction, transportation, and daily chemical industries. Notably, ethyl silicone rubber has attracted increasing attention as the elastomer material with the lowest known glass transition temperature. , Derived from the cross-linking of linear polydiethylsiloxane (PDES), with −Si–O–Si– as the main chain and –CH 2 CH 3 as the side group, ethyl silicone rubber exhibits a glass transition temperature of −145 °C.…”

Versatile Switchable Targeted Polysiloxanes for High-Resolution Visualization of Mitochondrial and Lysosomal Interactions during Ferroptosis

“…31−34 Polysiloxanes were well known for their excellent biocompatibility and stability. 35,36 Researchers favor polysiloxanes due to their biocompatibility, fascinating stability, and rich source depth. In addition, owing to its ease for functionaliza-tion and green synthesis, polysiloxanes promise to serve as ideal platforms for bioimaging.…”

“…Polysiloxanes were well known for their excellent biocompatibility and stability. , Researchers favor polysiloxanes due to their biocompatibility, fascinating stability, and rich source depth. In addition, owing to its ease for functionalization and green synthesis, polysiloxanes promise to serve as ideal platforms for bioimaging. − To fill this gap, we have constructed a polysiloxane fluorescent probe that could switchable target subcellular organelles and efficiently detects ONOO – based on the advantages of polysiloxane.…”

Corner-opened cage-silsesquioxane as a directional template for tripodal poly(methyl methacrylate)

“…In contrast to the symmetrical structure of CC-POSS, corner-opened POSS (CO-POSS) exhibits three silanol groups in the open moiety. 8 We have been developing CO-POSS materials through the functionalization of the three silanol groups, such as main-chain polymers, 9 side-chain polymers, 10 network polymers, 11 and nanofillers. 12 During a series of investigations, we found that CO-POSSs exhibit thermal stability comparable to that of the corresponding CC-POSS while the symmetry is effectively reduced.…”