Probing sub-nano level molecular packing and correlated positron annihilation characteristics of ionic cross-linked chitosan membranes using positron annihilation spectroscopy

doi:10.1039/c6cp07434k

	Probing sub-nano level molecular packing and correlated positron annihilation characteristics of ionic cross-linked chitosan membranes using positron annihilation spectroscopy
	Wei, L; Wei L(魏龙); Wang BY(王宝义); Zhang P(张鹏); Cao XZ(曹兴忠); Wang, BY; Zeng, MF; Zhang, P; Gao, MZ; Cao, XZ
刊名	PHYSICAL CHEMISTRY CHEMICAL PHYSICS
	2017
卷号	19 期号:5 页码:3616-3626
ISSN号	1463-9076
DOI	10.1039/c6cp07434k
文献子类	Article
英文摘要	Chitosan, CS, cross-linked with bivalent palladium has shown enhanced mechanical and thermal properties depending on the transformation of the structure at a microscopic scale. In the present study, CS directly cross-linked by palladium cation membranes (CS-cr-PM) was prepared through a solution-casting method. Mobility of chitosan chains were greatly reduced after crosslinking, making a great reduction in the swelling ratio studied by a water-swelling degree measurement, which led to an improvement in molecular chain rigidity. In order to investigate the chain packing at the molecular level in the ionic cross-linked CS system, the structure of chemically-crosslinked CS is investigated by means of the combined use of wide angle X-ray diffraction (WAXD) and infrared measurements, and a combination of positron annihilation lifetime spectroscopy (PALS) and simultaneous coincidence Doppler broadening (CDB) spectroscopy offers coherent information on both the free-volume related sub-nano level molecular packing and the chemical surrounding of free volume nanoholes in CS-cr-PM as a function of palladium salt loading. The variations in the free volume size and size distribution have been determined through the ortho-positronium (o-Ps) lifetime and its lifetime distribution. The studies showed that a strong interaction between CS molecules and palladium cations results in the change in crystallinity in formed CS-cr-PM leading to variational chain packing density. Meanwhile, significant inhibition effects on positronium formation due to doping are observed, which could be interpreted in terms of the existence of chloride ions. Applications of positron annihilation spectroscopy to study the microstructure and correlated positron annihilation characteristics of an ionic cross-linked CS system are systematically discussed.
电子版国际标准刊号	1463-9084
WOS关键词	DOPPLER-BROADENING SPECTROSCOPY ; FREE-VOLUME ; NANOCOMPOSITES ; LIFETIME ; TRANSPORT ; CATALYST ; FILMS ; PMMA
WOS研究方向	Chemistry ; Physics
语种	英语
WOS记录号	WOS:000395328100021
内容类型	期刊论文
源URL	[http://ir.ihep.ac.cn/handle/311005/285128]
专题	高能物理研究所_多学科研究中心
作者单位	中国科学院高能物理研究所
推荐引用方式 GB/T 7714	Wei, L,Wei L,Wang BY,et al. Probing sub-nano level molecular packing and correlated positron annihilation characteristics of ionic cross-linked chitosan membranes using positron annihilation spectroscopy[J]. PHYSICAL CHEMISTRY CHEMICAL PHYSICS,2017,19(5):3616-3626.
APA	Wei, L.,魏龙.,王宝义.,张鹏.,曹兴忠.,...&Xia, R.(2017).Probing sub-nano level molecular packing and correlated positron annihilation characteristics of ionic cross-linked chitosan membranes using positron annihilation spectroscopy.PHYSICAL CHEMISTRY CHEMICAL PHYSICS,19(5),3616-3626.
MLA	Wei, L,et al."Probing sub-nano level molecular packing and correlated positron annihilation characteristics of ionic cross-linked chitosan membranes using positron annihilation spectroscopy".PHYSICAL CHEMISTRY CHEMICAL PHYSICS 19.5(2017):3616-3626.