Insight into the self-adaptive deformation of kaolinite layers into nanoscrolls

• The definition of self-adaptive deformation of minerals was proposed.
• Evolution sequences of kaolinite from nanosheets to nanoscrolls were revealed
• Characteristics of kaolinite nanoscrolls were investigated.

Kaolinite layers get curled up into one-dimensional nanoscrolls automatically when they are exfoliated in methanol after intercalation with alkyltrimethylammonium salts. The intercalated molecules weaken the hydrogen bonding significantly, and provide space for kaolinite to roll up after their deintercalation. A mismatch of SiO tetrahedral sheet and AlO(OH) octahedral sheet of kaolinite leads to rolling up of the layer until reaching a stable morphology. During the intercalation and exfoliation processes, the kaolinite layer goes through a morphological evolution sequence i.e., from 3-dimensional particles to 2-dimensional lamella and then to 1-dimensional scroll (3D → 2D → 1D). The inner diameter of kaolinite nanoscroll varies between 10–35 nm, while the outer diameter is about 35 nm but most of them are smaller than 100 nm. The length of kaolinite nanoscroll is determined by the initial particle size. This paper presents a systematic analysis of morphological changes of kaolinite minerals and proposes the concept of self-adaptive deformation of minerals.

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