Figure 2 TEM photos of MTCFs@SIP@CBMA under different WBSA-SIPMTFs/WCBMA (a); effect of WBSA-SIPMTFs/WCBMA on the adsorption capacity and imprinting factor of MTCFs@SIP@CBMA (b)
Characterization of MTCFs@SIP@CBMA
Morphologies observation
SEM and TEM images of each product and EDS analysis results of MTCFs@SIP@CBMA are given in Figure 3. As can be seen from Figure 3A and E, MTFs presented a hollow fibrous structure with an average diameter of 105 nm. In addition, the cavities contained black nanoscale particles. Through analysis, it was believed that these nanoparticles with high mass thick contrast were the conversion products of FeCl3 during the carbonization of polymer nanofibers (TPNFs). Magnet and VSM tests displayed that MTCFs exhibited magnetic responsiveness, so it was inferred that these nanoparticles may be Fe3O4 or iron element. After the coating of imprinted layer, the surface of BSA-MTCFs@SIP became significantly rough compared with the smooth surface of MTCFs, and the fiber diameter increased slightly (Figure. 3b and f). The average diameter of BSA-MTCFs@SIP was121 nm, which was an increase of 16 nm compared to MTCFs. The calculated thickness of imprinting layer was 8 nm. This thickness was sufficient to achieve an effective imprinting of BSA with a size of 14 nm×4 nm×4 nm. SEM and TEM photos of MTCFs@SIP@CBMA are presented in Figure 3c and g. By measurement, the average diameter of MTCFs@SIP@CBMA fibers increased by 4 nm compared with that of BSA-MTCFs@SIP, indicating the successful graft of CBMA polymer chain. The thickness of CBMA layer was 2 nm. Compared Figures 3c with d, it was observed that the surface morphology of MTCFs@NIP@CBMA was not significantly different from that of MTCFs@SIP@CBMA. In the dark field image of MTCFs@SIP@CBMA (Figure 3h), it displayed a different degree of brightness and darkness on the tube wall, illustrating the coating of the PDA imprinted layer and the grafting of the CBMA polymer chain. The extremely bright nanoscale dots in the tube were inorganic magnetic nanoparticles. The EDS analysis results of MTCFs@SIP@CBMA are shown in Figure 3i-1. It can be seen that MTCFs@SIP@CBMA contained abundant C, N, O and Fe elements. The presence of N and O indicated that the surface of MTCFs was coated with PDA imprinted layer and CBMA polymer layer. Fe element was derived from magnetic nanoparticles.