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Surface-Induced Frustration in Solid State Polymorphic Transition of Native Cellulose Nanocrystals.
Reeta Salminen1, Niki Baccile2, Mehedi Reza3
1Department of Bioproducts and Biosystems, School of Chemical Engineering, Aalto University , P.O. Box 16300, 00076 Aalto, Finland.
Biomacromolecules
|May 3, 2017
Summary
Surface immobilization of cellulose nanocrystals (CNCs) during solid-state polymorphic transitions causes exfoliation. This effect, driven by guest molecule inclusion and substrate attachment, is not observed in bulk dispersions.
Area of Science:
- Materials Science
- Polymer Science
- Nanotechnology
Background:
- Interfaces typically influence polymer crystallization.
- This study investigates solid-state polymorphic transitions in cellulose nanocrystals (CNCs).
Purpose of the Study:
- To explore the effect of surface immobilization on solid-state polymorphic transitions of individual CNCs.
- To understand the mechanism of exfoliation in CNCs during transitions.
Main Methods:
- Solid-state polymorphic transition of cellulose I to cellulose III using ethylene diamine.
- Atomic force microscopy (AFM) to analyze CNC dimensions before and after transition.
- Comparison between immobilized and non-immobilized CNCs.
Main Results:
- Immobilized CNCs showed a 60% reduction in width (height) after transition.
- Exfoliation of van der Waals bonded sheets within CNCs was observed for immobilized samples.
- Non-immobilized CNCs in bulk dispersion showed no significant dimensional changes.
Conclusions:
- Surface immobilization induces exfoliation in CNCs during solid-state polymorphic transitions.
- The process involves stresses from guest molecule inclusion and substrate attachment.
- This exfoliation mechanism offers an analogy to 2D material delamination, like graphene.
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