title: Mechanism of kaolinite sheets curling via the intercalation and delamination process.
abstract: Kaolinite naturally occurs in the plate form for the interlayer hydrogen bond and the distortion and adaption of tetrahedron and octahedron. But kaolinite sheets can be exfoliated to nanoscrolls artificially in laboratory through multiple-step displacement intercalation. The driving force for kaolinite sheet to be curled nanoscroll originates from the size discrepancy of Si-O tetrahedron and Al-O octahedron. The displacement intercalation promoted the platy kaolinite sheets spontaneously to be scrolled by eliminating the interlayer hydrogen bond and atomic interaction. Kaolinite nanoscrolls are hollow tubes with outer face of tetrahedral sheet and inner face of octahedral sheet. Based on the theoretical calculation it is firstly reported that the minimum interior diameter for a single kaolinite sheet to be scrolled is about 9.08 nm, and the optimal 24.30 nm, the maximum 100 nm, which is verified by the observation of scanning electron microscope and transmission electron microscope. The different adaption types and discrepancy degree between tetrahedron and octahedron generate various curling forces in different directions. The nanoscroll axes prefer the directions as [100], [11¯0], [110], [31¯0], and the relative curling force are as follows, [31¯0]>[100]=[11¯0]>[110].
authors.affiliation: School of Geoscience and Surveying Engineering, China University of Mining & Technology, Beijing 100083, PR China. Electronic address: lixiaoguang12345@126.com.
authors.forename: Xiaoguang
authors.initials: X
authors.lastname: Li
authors.affiliation: School of Geoscience and Surveying Engineering, China University of Mining & Technology, Beijing 100083, PR China. Electronic address: lqf@cumtb.edu.cn.
authors.forename: Qinfu
authors.initials: Q
authors.lastname: Liu
authors.affiliation: School of Geoscience and Surveying Engineering, China University of Mining & Technology, Beijing 100083, PR China; School of Chemistry, Physics and Mechanical Engineering, Science and Engineering Faculty, Queensland University of Technology, 2 George Street, GPO Box 2434, Brisbane, Queensland 4001, Australia. Electronic address: h.cheng@cumtb.edu.cn.
authors.forename: Hongfei
authors.initials: H
authors.lastname: Cheng
authors.affiliation: School of Geoscience and Surveying Engineering, China University of Mining & Technology, Beijing 100083, PR China. Electronic address: szhang870119@hotmail.com.
authors.forename: Shuai
authors.initials: S
authors.lastname: Zhang
authors.affiliation: School of Chemistry, Physics and Mechanical Engineering, Science and Engineering Faculty, Queensland University of Technology, 2 George Street, GPO Box 2434, Brisbane, Queensland 4001, Australia. Electronic address: r.frost@qut.edu.au.
authors.forename: Ray L
authors.initials: RL
authors.lastname: Frost
keywords: Curling model; Delamination; Intercalation; Kaolinite; Nanoscroll