One‐pot synthesis of soluble and fluorescent aliphatic hyperbranched poly(amide‐imide) with solvent‐dependent emission

Abstract

Aliphatic hyperbranched poly(amide-imide) was facilely prepared by employing a functional thiolactone-maleimide monomer. Highly efficient, selective and quantitative properties of amine-maleimide Michael addition and aminolysis of a thiolactone guaranteed the generation of an ABB' thiol-yne intermediate without side products, followed by consecutive thiol-yne click reaction in one-pot. The hyperbranched structure of the poly(amide-imide) was confirmed by NMR spectroscopy and tripledetector GPC/SEC analysis. Additionally, due to the presence of aminosuccinimide fluorophores and intrinsic physical property of hyperbranched polymers, this aliphatic hyperbranched poly(amide-imide) possessed solvent-dependent emission and presented good solubility in various organic solvents.

Self-Assembling Nonconjugated Poly(amide-imide) into Thermoresponsive Nanovesicles with Unexpected Red Fluorescence for Bioimaging

“…More significantly, the red fluorescence of PEG-PAI4 in water was soundly retained with a quantum yield of 5.8% ( E m ∼ 580 nm), utilizing rhodamine 6G as a standard (Figure c). This was nearly 60-fold fluorescence enhancement of PAIs in water (typical ϕ < 0.1%). ,, …”

“…This was nearly 60-fold fluorescence enhancement of PAIs in water (typical ϕ < 0.1%). 18,19,21 Various strategies and factors can result in red-shifted emission, which primarily comprise π−π stacking, 26 electrostatic interactions, 27 hydrogen bond, 28 peripheral substitu-tion, 29−31 annulation, 32,33 trans−cis isomerization 34 and excited-state intramolecular proton transfer (ESIPT). 35 Looking into the structure of PEG-PAI4, it is indeed composed of four segments, namely PEG, aminosuccinimide fluorophore, PAI and diamine-136.…”

“…Besides, strong intermolecular interactions result in poor solubility and restrict their potential roles in biological applications . Recently, we circumvented these issues by employing a functional thiolactone-maleimide monomer via in situ PEGylation and provided aliphatic PAIs with unique blue/green fluorescence in organic solvents. − However, not only this wavelength emission could be interfered with autofluorescence of biological objects such as cells, tissues and organs, but also the fluorescence of PAIs considerably decreases or completely quenches in protic medium due to the formation of hydrogen bonds between the fluorophores and protic solvents, , which is disfavored similarly to the notorious aggregation-caused quenching (ACQ) effect and leads to great limitations in cell imaging and protein labeling.…”

Recent Advances in Structural Modifications of Hyperbranched Polymers and Their Applications

“…enhanced their solubility and induced low viscosity, resulting in their excellent performance in their application in the form of solid and powder coatings. 115,116 The use of OH-terminated HPEs has helped the development of coatings having low volatile organic compounds (VOC) (e.g., PU coatings). 117 The key factor for the application of HPs as coating materials is their ability to maintain the ratio of functional groups of reactants, as in case if the ratio of functional groups is not maintained, the presence of a large number of reactive functional groups results in the fast curing of coatings.…”

“…The introduction of several functional moieties that act as cross-linking groups (vinyl ether, acrylate, epoxy ring, OH groups, etc.) enhanced their solubility and induced low viscosity, resulting in their excellent performance in their application in the form of solid and powder coatings. , …”