Kamibe Takuma, Guégan Régis, Kunitake Masashi, Tsukahara Takehiko, Idota Naokazu, Sugahara Yoshiyuki
Department of Applied Chemistry, School of Advanced Science and Engineering, Waseda University, 3-4-1 Okubo, Shinjuku-ku, Tokyo 169-8555, Japan.
Global Center for Science and Engineering, Waseda University, 3-4-1 Okubo, Shinjuku-ku, Tokyo 169-8555, Japan.
Dalton Trans. 2022 Apr 20;51(16):6264-6274. doi: 10.1039/d1dt04355b.
Double-layered nanosheets containing pH-cleavable polymer networks between two niobate layers were prepared by copolymerization of -isopropylacrylamide and an acid-degradable crosslinker surface-initiated atom transfer radical polymerization on the surface of hydrated interlayers (interlayer I) of KNbO·3HO and subsequent exfoliation by the introduction of tetra--butylammonium (TBA) ions into anhydrous interlayers (interlayer II). Moreover, the double-layered nanosheets were converted into single-layered nanosheets by the cleavage of cross-linking points in polymer networks by lowering pH. Fourier transform infrared spectroscopy (FTIR) and thermogravimetry (TG) results showed that polymer networks were present, and nanosheets with a thickness of 10.8 ± 1.6 nm were observed by using an atomic force microscope (AFM) after exfoliation using TBA ions. The thickness of the nanosheets was decreased to 6.1 ± 0.9 nm by lowering the pH, and proton nuclear magnetic resonance (H NMR) and UV-vis spectroscopy showed that the degradation of the cross-linkers proceeded, suggesting that the cleavage of the cross-linking points led to the conversion of double-layered nanosheets into single-layered nanosheets.
通过在铌酸钾水合中间层（中间层I）表面进行N-异丙基丙烯酰胺与酸可降解交联剂的共聚反应及表面引发的原子转移自由基聚合，随后将四丁基铵（TBA）离子引入无水中间层（中间层II）进行剥离，制备了在两个铌酸酯层之间含有pH可裂解聚合物网络的双层纳米片。此外，通过降低pH值使聚合物网络中的交联点断裂，双层纳米片转变为单层纳米片。傅里叶变换红外光谱（FTIR）和热重分析（TG）结果表明聚合物网络存在，使用TBA离子剥离后，通过原子力显微镜（AFM）观察到厚度为10.8±1.6nm的纳米片。通过降低pH值，纳米片的厚度减小至6.1±0.9nm，质子核磁共振（H NMR）和紫外可见光谱表明交联剂发生降解，这表明交联点的断裂导致双层纳米片转变为单层纳米片。
