Conjugated Hyperbranched Poly(aryleneethynylene)s: Synthesis, Photophysical Properties, Superquenching by Explosive, Photopatternability, and Tunable High Refractive Indices

Abstract

Triphenylamine (TPA)-based conjugated hyperbranched poly(aryleneethynylene)s (PAEs), hb-P1/2, hb-P1/3, and hb-P1/4, were synthesized with high molecular weights and good solubilities through Sonogashira coupling reactions. These PAEs exhibited outstanding thermal stabilities and different emission behaviors. Tetraphenylethene (TPE)-containing hb-P1/2 fluoresced faintly in THF, although its light emission was enhanced by aggregate formation in aqueous media or in thin films, thereby exhibiting an aggregation-induced emission-enhancement (AIEE) effect. Whereas 1,1,2,3,4,5-hexaphenylsilole (HPS)-bearing hb-P1/3 showed no significant change in emission intensity with increasing water content in aqueous media, hb-P1/4, which consisted of TPA-fluorenone donor-acceptor groups, presented almost identical absorptions, but both positive and negative solvatochromic emissions in various solvents. A superquenching effect was observed in the picric-acid-detection process by using nanosuspensions of hb-P1/2. All of the polymers possessed good film formability. UV irradiation of the thin films induced simultaneous photobleaching and cross-linking, thus making them applicable in the fabrication of 2D and 3D patterns. Furthermore, the polymer films also showed high refractive indices, which were tunable upon exposure to UV light.

Porous Polymers Based on Aryleneethynylene Building Blocks

“…A hyperbranched polymer results if instead of an A n + B m approach, AB 2 monomers are polymerized. Tang et al show that one can produce hybrids between CMPs and hyperbranched polymers 10–11 – 10–13 by just really decreasing the concentration of the monomers and isolating the soluble parts of the reaction products. These polymers are emissive detectors for explosives and are highly film‐forming.…”

Branched polystyrene with high reflex index synthesized from selenium-mediated polymerization

“…According to the Lorentz–Lorenz equation, the introduction of substituents with high molar refractions and low‐molar volume groups have become the common approaches for most researchers to increase the refractive index of polymers . Traditional methods usually be adopted were (1) incorporating organic groups or consisting of highly conjugated structures, such as aromatic groups; (2) incorporation of halogen atoms, sulfur atoms and silicon atoms with high molar refractions into the backbone or side chain of polymers; (3) synthesizing polymers with enwrapped inorganic nanoparticles . Table showed the molar refractions of common atoms or groups.…”

Polymers for Luminescent Sensing Applications

“…Several conjugated hyperbranched polymers have been reported, which have many branching points but are soluble in organic solvents. Triphenylamine‐based conjugated hyperbranched polymer, P25 , was synthesized through Sonogashira coupling reaction of iodinated triphenylamine with aromatic diyne (Figure a) Although the coupling reaction between A 3 and B 2 type monomers usually produced a cross‐linked poly­mer, a soluble polymer could be obtained by controlling the polymerization time, solvent, monomer concentration, and feeding style. The polymer exhibited an aggregation‐induced emission enhancement.…”