Synthesis and characterization of multilayer core–shell structure hollow spheres with low density, favorable magnetic and conductive properties

Synthesis, characterisation, and evaluation of core–shell Fe 3 O 4 /SiO 2 /polypyrrole composite nanoparticles

“…After being coated by polypyrrole, the diffraction intensity of the wide peak between 18° and 25° of 2 θ increases obviously as shown in Fig. 3 c due to a marked increase in thickness of polypyrrole shell [17, 23], indicating that amorphous polypyrrole exists in the sample.…”

“…Polypyrrole nanoparticles display high electrically conducting, stability and biocompatibility, also supply amino groups on their backbone for therapeutic agents linking, and potentially provide a new photothermal therapy agent for cancer treatment [15,16]. Unfortunately, there is a bottleneck in the direct coating of polypyrrole on Fe 3 O 4 nanoparticles, thus a surfactant or intermediate layer or combination of them is indispensable [17][18][19]. Usually, the modification of surfactant requires a tediously long stirring process, and the surfactant could not link uniformly on the Fe 3 O 4 nanoparticles, which directly affect the coating of polypyrrole [16,18].…”

Synthesis and physical properties of electromagnetic polypyrrole composites via addition of magnetic crystals

“…41 Indeed, it has often been observed that the conductivity of PPy composites decreased with increasing the content of magnetic additives. 10,36,41,42,46 However, the opposite tendency has also been reported by many researchers. 11,40,43,44,47,[61][62][63]75,76 As shown in Table 3, the conductivity of the electromagnetic PPy composites is 43 In the above discussion, it has been shown that both a reduction and enhancement in conductivity are possible by incorporation of magnetic crystals into the PPy matrix.…”

“…The commonly employed preparation methods include simple blending, electrochemical processing, in situ polymerization and the one step chemical synthesis. The magnetic additives include metals such as iron, 5,34,80,81 cobalt 33 and nickel, 15,16,35 iron oxides such as Fe 3 O 4 , 6,11,[22][23][24][25][26][27][28][29][30]32,[41][42][43][44][45][46][47][48][49][50][51][52][53][54][55][56][57][58][59][60]85,86 γ-Fe 2 O 3 7,12,[62][63][64][65][66][67]…”

“…In general, a core-shell structure of the electromagnetic PPy composites is obtained by this method. For example, core-shell-structured electromagnetic PPy composites such as Ba(LaNd) 0.09 Fe 11.82 O 19 -PPy, 36 BaFe 12 O 19 -PPy, 9,38 spinel ferrite-PPy, 14,17,19,21,46,72,73,[77][78][79] Fe x O y -PPy, 11,12,[22][23][24][25][26][27][28][29][30][31][32] Ni-PPy 15,16 and SeFe 12 O 19 -PPy composites, 74,76 etc. have been prepared by the in situ polymerization method.…”