Green Topochemical Esterification Effects on the Supramolecular Structure of Chitin Nanocrystals: Implications for Highly Stable Pickering Emulsions
Journal article, 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

topochemistry

solid-state NMR

supramolecular organization

nematic structures

chitin nanocrystals

Author

Chiara Magnani

Universite de Mons

Mina Fazilati

Chalmers, Industrial and Materials Science, Engineering Materials

Roland Kádár

Wallenberg Wood Science Center (WWSC)

Chalmers, Industrial and Materials Science, Engineering Materials

Alexander Idström

Chalmers, Chemistry and Chemical Engineering, Applied Chemistry

Lars Evenäs

Chalmers, Chemistry and Chemical Engineering, Applied Chemistry

Wallenberg Wood Science Center (WWSC)

Jean Marie Raquez

Universite de Mons

Giada Lo Re

Wallenberg Wood Science Center (WWSC)

Chalmers, Industrial and Materials Science, Engineering Materials

ACS Applied Nano Materials

25740970 (eISSN)

Vol. 5 4 4731-4743

Subject Categories

Physical Chemistry

Polymer Technologies

Other Chemistry Topics

DOI

10.1021/acsanm.1c03708

PubMed

35492439

More information

Latest update

3/7/2024 9