Surface-Induced Frustration in Solid State Polymorphic Transition of Native Cellulose Nanocrystals

Abstract

ABSTRACT. The presence of an interface generally influences crystallization of polymers from melt or from solution. Here, by contrast, we explore the effect of surface immobilization in a direct solid state polymorphic transition on individual cellulose nanocrystals (CNCs), extracted from a plant-based origin. The conversion from native cellulose I to cellulose III crystal occurred via a 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 2 host-guest inclusion of ethylene diamine inside the crystal. 60% reduction in CNC width (height) in atomic force microscopy images suggested that when immobilized on a flat modified silica surface, the stresses caused by the inclusion or the subsequent regeneration resulted in exfoliation, hypothetically between the van der Waals bonded sheets within the crystal. Virtually no changes in dimensions were visible when the polymorphic transition was performed to non-immobilized CNCs in bulk dispersion. With reservations and by acknowledging the obvious dissimilarities, the exfoliation of cellulose crystal sheets can be viewed as analogous to exfoliation of 2D structures like graphene from a van der Waals stacked solid. Here, the detachment is triggered by an inclusion of a guest molecule inside a host cellulose crystal and the stresses caused by the firm attachment of the CNC on a solid substrate, leading to detachment of molecular sheets or stacks of sheets.

Advanced Materials through Assembly of Nanocelluloses

“…c) In a cellulose I crystal, hydrogen bonded sheets that are stacked on top of each other with van der Waals bonding that can be exfoliated in a polymorphic transition. Reproduced with permission . Copyright 2017, American Chemical Society.…”

“…Both CNFs and CNCs are based on the native microfibril structure which bears an amphiphilic character as cellulose I crystal possesses both hydrophilic planes, exposing the equatorial OH groups, and hydrophobic planes, exposing the axial CH functionalities (Figure c) . This amphiphilicity of the crystal can be used both in CNFs and CNCs after their preparation for exfoliation of the hydrophobic planes to yield entirely distinct nanoobjects (Figure c) . Overall, the amphiphilic nature of nanocelluloses is beneficial for their use as emulsion stabilizers.…”

Extended ensemble molecular dynamics study of cellulose I–ethylenediamine complex crystal models: atomistic picture of desorption behaviors of ethylenediamine

“…In comparison with a native cellulose crystal, the enhanced accessibility and chemical reactivity of the cellulose III I crystal have been attributed to not only the physical nature of the latter form but also crystal degradation resulting from amine treatments. Salminen et al reported the solid-state polymorphic transition of cellulose nanocrystals immobilized on a chemically modi ed silicon surface from cellulose I to III I through its EDA complex (Salminen et al 2017). The width of the cellulose III I nanocrystals decreased to half the original size of the cellulose I nanocrystals, whereas their length remained unchanged.…”

The Effect of Polymorphism on the Kinetics of Adsorption and Degradation: A Case of Hydrogen Chloride Vapor on Cellulose

“…Cellulose, the natural polysaccharide responsible for the structural scaffold of all plants cells, is no different. The native crystalline order of cellulose, as dictated by biosynthesis, can be deliberately modified with specific treatments, leading to substantial alterations in the material behavior.…”

“…[9][10][11] Cellulose, the natural polysaccharide responsible for the structural scaffold of all plants cells, is no different. The native crystalline order of cellulose, as dictated by biosynthesis, [12] can be deliberately modified with specific treatments, [13][14][15] leading to substantial alterations in the material behavior.Here, the degradation of three artificially prepared cellulose polymorphs during acid catalyzed hydrolysis (Figure 1) is explored. Chemical degradation of cellulose is a topical issue for two principal reasons: obtaining cellulosic nanomaterials for novel renewable applications [16][17][18] as well as deriving small molecular substances, namely commodity chemicals or sugars that are subsequently used for fermentation for biofuel production.…”