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Titanate Nanosheets/Cellulose Composite Showing Improved Crystallinity and Decreased Water Wettability by Gamma-Irradiation
Author(s)
Tariwong, Yaowaluk
Pulphol, Phieraya
Sangtawesin, Tanagorn
Seriwattanachai, Chaowaphat
Kanjanaboos, Pongsakorn
Pakawanit, Phakkhananan
Chanlek, Narong
Charoonsuk, Thitirat
Onoda, Hiroaki
Date Issued
November 25, 2025
Type
Article
Abstract
While molecularly thin nanosheets have been increasingly studied as functional coatings, their use as a hydrophobic and γ-irradiation-tolerant component in biologically derived matrices is to be demonstrated. Herein, simple dip-coating was employed to fabricate titanate nanosheets/cellulose composites, which were subjected to γ-irradiation up to 50 kGy. Their surface chemistry was evaluated by water contact angle (WCA) measurements and X-ray photoelectron spectroscopy (XPS). Upon irradiation, the WCA of all samples nonmonotonically increased in three stages from ∼29 to 50° (noncoated) and ∼46 to 80° (composite, optimized at ∼1.2 wt %Ti loading, or 0.2 mg·cm–2). The titanium content and the 4+ valence did not change with the dose, suggesting the radiolytic stability. The dual surface modification occurs while cellulose fiber morphology and nanoscale mechanical properties are preserved. The increased WCA at the cellulose-part is explained by the γ-irradiation-induced crystallization according to the increased crystallinity index and improved thermal stability. At the other component, nanosheet coating results in increased surface roughness and diminished water–surface interactions. The latter is deduced from DSC measurements of water evaporation from pristine and 50 kGy-irradiated Cs0.7Ti1.825O4layered crystal-a nanosheet precursor. Our work suggests further exploration of nanosheets with diverse structures and compositions as coatings or fillers, which could find applications in γ-irradiation-sterilized barrier films.
Citation
Langmuir, 41(46), 31569-31579, 2025