X-ray Spectroscopy Study of the Atomic and Electronic Structure of Polyacrylonitrile-Based Nanocomposites at Different Stages of Formation

Microphase Separation 3D Printing of Binary Inorganic Polymer Precursors to Prepare Nanostructured Carbon‐Ceramic Multimaterials

“…[ 42 ] In the PIMS carbon‐ceramic multimaterials, an energy shift of 1.35 eV to the high‐energy region was observed, corresponding to C1s (C─H) → σ*C═C transitions in PAN‐derived materials. [ 41,42 ] The broadening of C4 in the carbon‐ceramic multi‐materials suggests a mixed sp 3 bonding environment, from spectral contributions of Si‐containing precursor (SMP‐10) and the N‐containing precursor (PAN) on the electronic structure, in agreement with our C1s XPS results (Figure S8, Supporting Information). The C5 peak, positioned at ≈ 303 eV, is associated with C 1s→ σ∗C═N, and sp 3 σ*C─C transitions, [ 40,41,44 ] correlated to AN and SMP‐10 contributions, respectively.…”

“…[ 42,44 ] The distinctive feature denoted as C3 is associated with either to C1s→π*C═O and/or C1s (C≡N) → π*C≡N transitions. [ 40,41,43 ] Despite its heightened intensity in AN‐rich ceramics (wt ratio SMP‐10/AN = 0.4/0.6), this peak exhibit discrete variations among the other AN/SMP wt ratios. For the material 3D printed in the absence of AN (wt ratio SMP‐10/AN = 1.0/0.0), the C3 feature primarily arises from oxygenated carbon species, yielding a less intense signal.…”

“…Supporting Information). The next peak, C2, associated with C1s(C─H) → 𝜎*C─H transitions, [40][41][42]44] remained consistent across SMP-10/AN wt ratios of 0.4/0.6, 0.5/0.5, and 0.6/0.4, exhibiting higher intensity than that in wt ratio SMP-10/AN = 1.0/0.0. This suggests a facilitated release of hydrogenated species in the absence of AN.…”

“…NEXAFS measurements at the C K-edge exhibited peaks corresponding to excitations of the 1s electrons of the carbon atom into the lowest unoccupied molecular orbitals of 𝜋 * (C1 to C3) and 𝜎 * (C4 to C5) transitions (Figure 3A). [39][40][41][42] Peak C1, associated with 𝜋* C = C and 𝜋* C = N transitions [39][40][41]43] exhibited consistently high intensity in both PAN and SMP-10 derived ceramic materials, suggesting a prevalence of sp 2 -hybridized C content in these compositions. The slightly decrease in the sp 2 carbon environment intensity in PIMS carbon-ceramic materials is likely shaped by the interplay of distinct carbon configurations arising from SMP-10 and AN.…”

“…In the PIMS carbon-ceramic multimaterials, C5 peak was more pronounced, similarly, to reported PAN-derived materials. [41] The N K-edge NEXAFS spectra revealed distinctive features denoted as N1, N2, and N3, corresponding to 𝜋* transitions from pyridinic-N, pyrrolic-N, and graphitic-N, respectively, while peak N4 originated from N1s→ 𝜎* transitions involving N─C bonds (Figure 3B; Table S7, Supporting Information). [39,40,43,45] The relative energy positioning of N1, N2, and N3 consistently supports the N1s XPS assignments (Figure S8, Supporting Information), although an additional feature, N4, was identified in the NEXAFS spectra.…”