期刊
APPLIED SURFACE SCIENCE
卷 258, 期 17, 页码 6665-6671出版社
ELSEVIER
DOI: 10.1016/j.apsusc.2012.03.110
关键词
Poly(L-lactic acid) nanofibers; Thermally induced phase separation; AFM; Nanoindentation
类别
资金
- National Basic Research Program of China [2012CB619100]
- National Natural Science Foundation of China [50830101, 51072056]
- Program for New Century Excellent Talents in University [NCET-08-0210]
- Program for Changjiang Scholars and Innovative Research Team in University [IRT 0919]
The surface morphology, crystalline structure and nanomechanical properties of poly(l-lactide) (PLLA) samples prepared via thermally induced phase separation (TIPS) process have been investigated by scanning electron microscopy (SEM), attenuated total reflection-Fourier transform infrared spectroscopy (ATR-FTIR), wide-angle X-ray diffraction (WAXD), atomic force microscopy (AFM), force spectroscopy and nanoindentation. Typical nanofibrous scaffold was obtained at -24 degrees C (NF sample) while a denser matrix with some plateletlike structure was obtained at 15 degrees C (PL sample). The NF sample has a higher crystallinity with alpha'-form crystals while the PL sample has alpha-form crystals embedded in a largely amorphous matrix. The two kinds of samples have differences in the chain conformation with a more restricted backbone vibration and stiffened segmental motion in NF samples. The NF samples have a higher adhesion force although both samples showed a heterogeneous distribution of adhesion force on the surface based on force spectroscopy analysis. The alternating distribution of domains with higher and lower adhesion force exhibited a banded pattern on PLLA nanofibre. This pattern is proposed to reflect the distribution of crystal-rich and amorphous-rich domains in the semicrystalline samples. AFM-based nanoindentation test indicated that the nanofibrous NF samples can have more significant plastic deformation and creep than the largely amorphous PL samples. The sliding of the crystal-rich domains along the fibrils would account for this increased plasticity of the nanofiber. (C) 2012 Elsevier B. V. All rights reserved.
作者
我是这篇论文的作者
点击您的名字以认领此论文并将其添加到您的个人资料中。
推荐
暂无数据