Conductive polypyrrole (PPy) is an excellent polymer material for microwave absorption, which is vital for reducing electromagnetic interference (EMI) for electronic devices. To improve the microwave absorption capability and enhance the thermal stability and mechanical ductility of conductive PPy, metallic magnetic nanoparticles can be added to form PPy nanocomposites. In this paper, we present the first study to compute the electromagnetic properties of PPy nanocomposites based on the first principles method. It is discovered that (1) while doping can improve the microwave absorbing proper-ties of PPy material, the absorption performance does not necessarily increase with the number of doping position; (2) conductivity and absorption coefficient increase significantly for the PPy nanocomposite compared with PPy. The dielectric loss is more than 2 at about 2 eV; (3) reflectivity and absorption coefficient decrease with the increase of PPy content in PPy/Co nanocomposite; (4) the average magnetic moment of the PPy nanocomposite is the same as that of pure nanoparticles, and this indicates that only nanoparticles generate magnetic loss for the nanocomposite.
Well-defined P4VP-b-PBLG diblock polymer composed of poly (4-vinylpyridine) (P4VP) and poly (γ-benzyl-L-glutamate) (PBLG) was synthesized by click reaction with alkyne-and azide-functionalized homopolymers. Besides, P4VP blocks were synthesized by copper-mediated atom transfer radical polymerization (ATRP) with a chlorine-containing alkyne bifunctional initiator, and the azido-terminated PBLG homopolymers were synthesized by ring-opening polymerization (ROP) of γ-benzyl-L-glutamate with an amine-containing azide initiator. In addition, the synthesized P4VP-b-PBLG with different block ratios has been characterized by proton nuclear magnetic resonance ( 1 H NMR), Gel permeation chromatograph (GPC) and fourier transform infrated spectroscopy (FT-IR). Then, the self-assembly behaviors of P4VP-b-PBLG have been studied by changing parameters like dripping speed and block ratio. The morphologies of self-assembly of spherical, disk-like and ellipsoid-like shape particles have been observed and analyzed by scanning electron microscopy (SEM). These results have provided guidelines for the design of macromolecular self-assembly.
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