Green Topochemical Esterification Effects on the Supramolecular Structure of Chitin Nanocrystals: Implications for Highly Stable Pickering Emulsions
Artikel i vetenskaplig tidskrift, 2022

In nature, chitin is organized in hierarchical structures composed of nanoscale building blocks that show outstanding mechanical and optical properties attractive for nanomaterial design. For applications that benefit from a maximized interface such as nanocomposites and Pickering emulsions, individualized chitin nanocrystals (ChNCs) are of interest. However, when extracted in water suspension, their individualization is affected by ChNC self-assembly, requiring a large amount of water (above 90%) for ChNC transport and stock, which limits their widespread use. To master their individualization upon drying and after regeneration, we herein report a waterborne topochemical one-pot acid hydrolysis/Fischer esterification to extract ChNCs from chitin and simultaneously decorate their surface with lactate or butyrate moieties. Controlled reaction conditions were designed to obtain nanocrystals of a comparable aspect ratio of about 30 and a degree of modification of about 30% of the ChNC surface, under the rationale to assess the only effect of the topochemistry on ChNC supramolecular organization. The rheological analysis coupled with polarized light imaging shows how the nematic structuring is hindered by both surface ester moieties. The increased viscosity and elasticity of the modified ChNC colloids indicate a gel-like phase, where typical ChNC clusters of liquid crystalline phases are disrupted. Pickering emulsions have been prepared from lyophilized nanocrystals as a proof of concept. Our results demonstrate that only the emulsions stabilized by the modified ChNCs have excellent stability over time, highlighting that their individualization can be regenerated from the dry state.

Pickering emulsions

colloidal rheology


solid-state NMR

supramolecular organization

nematic structures

chitin nanocrystals


Chiara Magnani

Universite de Mons

Mina Fazilati

Chalmers, Industri- och materialvetenskap, Konstruktionsmaterial

Roland Kádár

Wallenberg Wood Science Center (WWSC)

Chalmers, Industri- och materialvetenskap, Konstruktionsmaterial

Alexander Idström

Chalmers, Kemi och kemiteknik, Tillämpad kemi

Lars Evenäs

Chalmers, Kemi och kemiteknik, Tillämpad kemi

Wallenberg Wood Science Center (WWSC)

Jean Marie Raquez

Universite de Mons

Giada Lo Re

Wallenberg Wood Science Center (WWSC)

Chalmers, Industri- och materialvetenskap, Konstruktionsmaterial

ACS Applied Nano Materials

25740970 (eISSN)

Vol. In Press


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