Eu^(3+)Coordinated Hyperbranched Polysiloxane with Multicolor Emission and Long Fluorescence Lifetime

Comprehensive Summary,Hyperbranched polysiloxanes have attracted increasing interest due to their unique fluorescence properties.However,the relatively short emission wavelength and low fluorescence lifetime are still the main obstacles to their broader application.In this study,we first synthesized aβ-diketone contained hyperbranched polysiloxane with excitation-dependent multicolor emission.Further through the coordination of HBPSi-NMDEA with Eu^(3+)ion,a hybrid luminescent material was prepared.It exhibited not only aggregation-induced red emission at 613 nm,but also a long fluorescence lifetime of 681.45μs.Particularly,it showed highly sensitive reversible fluorescence response to temperature variation,thus displaying the potential to be used in fluorescence temperature detection.

Construction of fluorescent hyperbranched polysiloxane-based clusteroluminogens with enhanced quantum yield and efficient cellular lighting

Owing to its designability and intrinsic fluorescence,non-conjugated hyperbranched polysiloxane(HBPSi)has attracted widespread attention in biological filed,while it is still severely restricted by low fluorescence efficiency.So,in this paper,we introduced disulfide into HBPSi improving their luminescence properties and synthesized different molecular weight HBPSi(P1,P2,and P3).Surprisingly,P1 exhibited ultrahigh quantum yield up to 47.81%.Meanwhile,experiments applied with theoretical calculations were employed to explore the fluorescence mechanism,which is attributed to efficient restricting of non-radiative decay by clusteroluminogens formed with the cooperation of hyperbranched structure and double hydrogen bonding.In addition,the biocompatibility of P1 was verified by co-culture with MC3T3-E1 and P1 lighted up mouse fibroblast cells without fluorescent dyes.This work designed a novel fluorescent polymer with ultrahigh fluorescence quantum yield and cell imaging ability,which is promising in visualization diagnosis and treatment of tumor.

Preparation of Low-dielectric Permittivity Polyimide Resins with High Surface Activity from Chemically Bonded Hyperbranched Polysiloxane

Thermosetting resin matrix is the key component of advaneed wave-tra nsparent composites,where low dielectric constant,excellent processability,high thermal stability,as well as good bonding ability are required for resins.Herein,we prepared a series of phenylethynyl terminated polyimide(PI)resins by grafting amine-functi onalized hyperbra nched polysiloxane(HBPSi)to PI chains during the in situ polymerization.The effects of HBPSi on the processability of oligomers,molecular packing,thermal stability,dielectric property and bonding ability to reinforce Kevlar fibers of the cured PI/HBPSi composite resins have been examined in detail.The dielectric constants of the cured composite resins were greatly reduced from 3.29 to 2.19 without compromising its processability and thermal stability.Meanwhile,the 10 wt%HBPSi-containing PI resin demonstrated better bonding ability to reinforce fibers with the in terfacial shear strength(IFSS)of 37.64 MPa,compared with that of neat PI-6 matrix(27.34 MPa),and better adhesion to metal with the lap shear strength of 10.48 MPa,50%higher than that of neat resin PI-6(6.98 MPa).These resultant PI/HBPSi composite resins exhibit excellent comprehensive properties,indicating their great potential as low-dielectric constant resin matrix in radar radome.