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Atomic Layer Deposition of Metal Oxide on Nanocellulose for Enabling Microscopic Characterization of Polymer Nanocomposites
Author(s) -
Septevani Athanasia A.,
Evans David A. C.,
Hosseinmardi Alireza,
Martin Darren J.,
Simonsen John,
Conley John F.,
Annamalai Pratheep K.
Publication year - 2018
Publication title -
small
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 3.785
H-Index - 236
eISSN - 1613-6829
pISSN - 1613-6810
DOI - 10.1002/smll.201803439
Subject(s) - materials science , nanocomposite , polymer , nanocellulose , polyurethane , atomic layer deposition , coating , layer (electronics) , chemical engineering , characterization (materials science) , amorphous solid , scanning electron microscope , polymer nanocomposite , transmission electron microscopy , nanotechnology , oxide , composite material , cellulose , chemistry , metallurgy , organic chemistry , engineering
Analysis of cellulose nanocrystals (CNCs) at low volume fractions in polymer nanocomposites through conventional electron microscopy still remains a challenge due to insufficient contrast between CNCs and organic polymer matrices. Herein, a methodology for enhancing the contrast of CNC, through atomic layer deposition (ALD) of alumina (Al 2 O 3 ) on CNCs is demonstrated. The metal oxide coated CNC allows clear visualization by transmission electron microscopy, when they are dispersed in water and polyol. A coating of about 6 ± 1 nm thick alumina layer on the CNC is achieved after 50 ALD cycles. This also enables the characterization of CNC dispersion/orientation (at 0.2 wt% loading) in an amorphous cellular system rigid polyurethane foam (RPUF), using backscattered electron microscopy with energy‐dispersive X‐ray spectroscopy. Microscopic analysis of the RPUF with alumina‐coated CNC confirms that the predominant alignment of CNC occurs in a direction parallel to the foam rise.