RESUMEN
Carbon dots (CDs), as a kind of zero-dimensional nanomaterials, have been widely synthesized by bottom-up methods from various precursors. However, the formation mechanism is still unclear and controversial, which also brings difficulty to the regulation of structures and properties. Only some tentative formation processes were postulated by analyzing the products obtained at different reaction times and temperatures. Here, the effect of crosslinking on the formation of carbonized polymer dots (CPDs) is explored. Crosslinking-induced nucleation and carbonization (CINC) is proposed as the driving force for the formation of CPDs. Under hydrothermal synthesis, the precursors are initiated to polymerize and crosslink. The crosslinking brings higher hydrophobicity to generate the hydrophilic/hydrophobic microphase separation, which promotes dehydration and carbonization resulting in the formation of CPDs. Based on the principle of CINC, the influence factors of size are also revealed. Moreover, the dissipative particle dynamics (DPD) simulation is employed to support this formation mechanism. This concept of CINC will bring light to the formation process of CPDs, as well as facilitate the regulation of CPDs' size and photoluminescence.
RESUMEN
Special separation membranes are widely employed for separation and purification purposes under challenging operating conditions due to their low energy consumption, excellent solvent, and corrosion resistance. However, the development of membranes is limited by corrosion-resistant polymer substrates and precise interfacial separation layers. Herein, polyaniline (PANI) is employed to achieve insitu anchoring of multiple interfaces, resulting in the fabrication of polyaniline@graphene oxide/polyether ether ketone (PANI@GO/PEEK) membranes. Insitu growth of PANI achieves the adequate bonding of the PEEK substrate and GO separation interface, which solves the problem of solution processing of PEEK and the instability of GO layers. By bottom-up confined polymerization of aniline, it could control the pore size of the separation layer, correct defects, and anchor among polymer, nano-separation layer, and nano-sheet. The mechanism of membrane construction within the confined domain and micro-nano structure modulation is further explored. The membranes demonstrate exceptional stability realizing over 90% rejection in 2 m HCl, NaOH, and high temperatures. Additionally, -membranes exhibit remarkable durability after 240 days immersion and 100 h long-term operation, which display the methanol flux of 50.2 L m-2 h-1 and 92% rejection of AF (585 g mol-1 ). This method substantially contributes to special separation membranes by offering a novel strategy.