Detailed mechanism of aniline nucleation into more conductive nanofibers

Abstract A large number of studies have been focused on synthesis optimization of conductive hydrogels for medical and sensor approaches. Heterogeneous nucleation of aniline monomers is resulted from secondary nucleation that not only depends on number of reaction groups but also system temperature. In this study, 4 °C was examined as a critical temperature applying limited mode of heterogeneous nucleation. Our observations showed this undercooling condition can behave in a cooperative manner with the number of carboxylate groups. Herein, polyacrylic acid-based hydrogel was obtained by different ratios of acrylic acid (AA)/ N , N ′-methylenebisacrylamide (MBAA) as 18.77 and 14.03. The based hydrogels exposed carboxylate terminates as nucleation centers for aniline cations. The smaller ratio of AA/MBAA produced the based-hydrogels with the higher number of reaction points for aniline monomers. Accordingly, the higher nucleation number of corresponding monomers leads to larger ratio of aniline/Ammonium persulfate (APS) at growth phase. Therefore, secondary nucleation of aniline monomers was limited by undercooling condition at 4° C and 3D interconnected nanofibers resulted by limited heterogeneous nucleation. The corresponding nanofibers showed higher conductivity value compared to 1D nanofibers which was resulted as a function of homogeneous nucleation.