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傅里叶变换红外(FT-IR)光谱、表面压力-分子面积(π-A)等温线和原子力显微镜(AFM)结果表明,聚乙烯吡咯烷酮(PVP)与胆固醇分子(Chol)在溶液中和气/液界面上可通过氢键作用形成刷状的超分子聚合物PVP-Chol。当表面压力低于2.5 m N?m~(-1)时,界面膜主要由富含胆固醇的微区与PVP-Chol纳米纤维构成的微区共存。在相对较低的表面压力下(<2.5 m N?m~(-1)),PVP-Chol微区形貌随界面膜压缩发生有序的变化:从最初的无规结构逐渐变为月牙形、心形和圆形结构;表面压超过2.5 m N?m~(-1)后,圆形的PVP-Chol微区最终消失并转变为少量的纤维聚集体结构。值得注意的是,在1.0 m N?m~(-1)之前,PVP-Chol纳米纤维高度随AFM成像过程中压电陶瓷外加电压的变化在1.8到4.3 nm之间出现了可逆转变,表明扫描探针针尖与样品之间的作用力可诱导超分子聚合物刷PVP-Chol发生从圆柱状到椭柱状的可逆结构转变。
Fourier Transform Infrared (FT-IR) spectroscopy, surface pressure-molecular area (π-A) isotherm and atomic force microscopy (AFM) results showed that polyvinylpyrrolidone (PVP) and cholesterol molecule (Chol) The liquid interface can form a brush-shaped supramolecular polymer PVP-Chol through hydrogen bonding. When the surface pressure is lower than 2.5 mN? M ~ (-1), the interfacial membrane coexists mainly with the microdomains which contain cholesterol and PVP-Chol nanofibers. At relatively low surface pressure (<2.5 m N? M -1), the morphologies of PVP-Chol domains changed orderly with the interface membrane compression: from the initial random structure to the crescent shape , Heart-shaped and circular structures. After the surface pressure exceeds 2.5 m N? M -1, the circular PVP-Chol domains eventually disappear and turn into a small amount of fiber aggregate structure. It is noteworthy that before 1.0 m N? M -1, the PVP-Chol nanofiber height reversibly changed from 1.8 to 4.3 nm with the change of the applied voltage of the piezoelectric ceramic during AFM imaging, indicating that the scanning The force between the tip of the probe and the sample induced a reversible structural transition from the columnar shape to the elliptical shape of the supramolecular polymer brush PVP-Chol.