pH and thermo responsive aliphatic tertiary amine chromophore hyperbranched poly(amino ether ester)s from oxa‐Michael addition polymerization

Abstract

In this research, we developed a novel and facile strategy to prepare aliphatic tertiary amine chromophore hyperbranched poly(amino ether ester)s with pH and thermo responsiveness via phosphazene base (t-BuP 2) catalyzed oxa-Michael addition polymerization of triethanolamine with ethylene glycol diacrylate at room temperature. UV-vis and fluorescence analyses results showed that the tertiary amine at branching point for hyperbranched poly(amino ether ester)s is very important to retain strong blue fluorescence of tertiary amine chromophore. Moreover, the hyperbranched poly(amino ether ester)s exhibit an aggregation caused quenching (ACQ) fluorescence, solvent induced red-shifted emission, molecular weight, and temperature dependent emission characters. More interestingly, the hyperbranched poly(amino ether ester)s show extreme acid induced quenching fluorescence phenomenon, and also display good water solubility, specific recognition of Fe 3+ ion, low cytotoxicity, and bright cell imaging, which could serve as a microenvironmentresponding fluorescent probe for application in chemical sensing, cell imaging, drug delivery, or disease diagnostics. This research provides a versatile method for the preparation of stimuli-responsive aliphatic tertiary amine chromophore polymers, and supplies ideas for researchers to explore other unconventional fluorescent polymers for application. K E Y W O R D S aliphatic tertiary amine chromophore, oxa-Michael addition polymerization, phosphazene base, hyperbranched poly(amino ether ester)s, stimulus responsiveness

Nontraditional Organic/Polymeric Luminogens with Red‐Shifted Fluorescence Emissions

“…Based on the type of heteroatoms other than carbon and hydrogen atoms in the nonconventional chromophores, the NTLs can be roughly classified into following categories (Figure 1) 1) Oxygen-containing NTLs: alcohols (d-fructose, d-(+)-xylose, d-galactose, and pentaerythritol), [30] ethers [poly(ethylene glycol) (PEG), [31] and hyperbranched polyether epoxy (EHBPE)], [23] carboxylic acids [poly(acrylic acid) (PAAc)], [32] anhydrides [poly(itaconic anhydride) (PITA), [33] and poly(maleic anhydride)], [16,34] and esters [polycarbonate, [35] and poly(lactic acid) binary blends]. [36] 2) Nitrogen-containing NTLs: amines [poly(amido amine) (PAMAM), [37,38] hyperbranched poly(amino ester) (PAE), [39,40] and poly(amino ether ester)], [41] imines [linear or hyperbranched polyethyleneimine (PEI)], [42][43][44] oximes (hexanal oximes), [11] nitriles [polyacrylonitrile (PAN)], [17] amides [polyacrylamide (PAAm), [45] poly(N-isopropylacrylamide) (PNIPAM), [32] poly(ether amide) (PEA), [46] poly(esteramide-ether) (PEAE), [47] and poly(amido acids)], [48] imides (polysuccinimide), [20,22] polyurethane, [49,50] amino acids, [51,52] and lactams [polyvinylpyrrolidone (PVP), [53] and poly(Nvinylcaprolactam) (PNVCL)]. [54] 3) Sulfur-containing NTLs: thiols (cysteine), sulfones (polysulfone), [55] sulfonic acids [perfluorosulfonate ionomers (PFSI)], [10] sulfonates [poly(4-vinylpyridine)butane-1sulfonate (PVP-S)], [56] and thiourea.…”

Hydrated Hydroxide Complex Dominates the AIE Property of Nonconjugated Polymeric Luminophores

“…From these results, we can conclude that hydrated water complexes are crucial for stabilize the emission center of nonconventional polymeric luminogens and these results provide an effective method for controlling these ubiquitous weak interactions. The previously reported abnormal emission phenomena for nontraditional AIE luminogens now can be readily understood due to the formation of diversity of PBIS with the assistance of hydrated hydroxide complexes at the confined nanospace, including pH and thermo sensitive photoemission, 26,27,42 solvatochromic effect, 24,25 oxidation-controlled photoemission 28,43 and molecular weightdependent fluorescence. 16…”

Synthesis of thermoresponsive nonconjugated fluorescent branched poly(ether amide)s via oxa-Michael addition polymerization

“…The cell viability of the polymers was investigated in HeLa and A549 cell lines by MTT assay, the absorbance being measured with an Infinite F50 microplate analyzer at 562 nm. 60 The cell fluorescence images of the polymers were obtained using a Nikon Eclipse TS100 inverted fluorescent microscope with excitation at 395 nm.…”

“…59 In our previous study, thermoresponsive polymers were easily prepared via oxa-Michael addition polymerization due to the formation of hydrophilic groups such as -OH and -Oand hydrophobic groups including -CH 3 and -CH 2 CH 3 in the polymer backbone. 60 Herein, a series of thermoresponsive nonconjugated fluorescent branched poly(ether amide)s with tunable LCST are synthesized following a straightforward method based on the oxa-Michael addition polymerization of commercially available trimethylolpropane (TMP), trimethylolethane (TME), and N,N′-methylenebis(acrylamide) (MBA) using the phosphazene base t-BuP 2 as a catalyst at room temperature (Scheme 1). The structure, fluorescence properties, thermoresponsiveness, and application of the obtained nonconjugated branched poly(ether amide)s are investigated in detail.…”