Productive Synthesis and Properties of Polydiaminoanthraquinone and Its Pure Self-Stabilized Nanoparticles with Widely Adjustable Electroconductivity

摘要

Wholly aromatic poly(1,5-di-aminoanthraquinone)(PDAA)particles were productively synthesized for the first time by chemically oxidative polymerization of 1,5-diaminoanthra-quinone(DAA)by using CrO3,K2Cr2O7,K2CrO4,or KMnO4 as oxidants in acidic DMF.The effects of the oxidant species,oxidant/DAA ratio,polymerization temperature,and medium on the polymerization yield,macromolecular structure,size,electro-conductivity,solubility,solvatochrom-ism,thermostability,photolumines-cence,and silver-ion sorption of the PDAA particles were systematically studied by IR,UV/Vis,fluorescence,and solid-state ~(13)C NMR spectroscopies,wide-angle X-ray diffraction,scan- ning and transmission electron microscopies,and laser particle-size,differential scanning calorimetry(DSC),and thermal gravimetric(TG)analyses.It seems that the DAA is oxidatively polymerized at the 1,4-and 5,8-posi-tions.Surprisingly,the chemical oxidative polymerization of DAA with CrO3 at 0°C in H2SO4/DMF in the absence of external stabilizer simply affords novel PDAA nanoparticles of around 30 nm in diameter with high purity,clean surfaces,inherent semiconductivi- ty,and self-stability that can be ascribed to the presence of a large number of 1,4-benzoquinone units that are negatively charged on their macromolecular chains.The polymers exhibit a high thermal stability at temperatures below 400 °C.Two unique nanoeffects were found,namely the strongest silver-ion adsorbability and photoluminescence of the PDAA nanoparticles.This gives a facile and general route for the application of the versatilities of PDAA nanomaterials.The PDAA particles are good semiconductors with a widely adjustable conductivity that moves across seven orders of magnitude through simple HClO4 redoping or Ag~+ sorption,as expected.