Functional surface coatings from tailor-made long-chain hydroxypropyl cellulose ester nanoparticles
Hydroxypropyl cellulose (HPC)-esters were prepared by a homogeneous reaction of HPC with fatty acid chlorides. The effects of different solvent systems and reaction additives were evaluated, and plain, dried THF was established as best system in terms of toxicity, targeted synthesis of desired degree of substitution (DS), chain degradation and ease of workup. Moreover, pyridine/4-dimethylaminopyridine (4-DMAP) was found to be the fastest system overall. The reaction kinetics with different fatty acids—lauric, myristic, palmitic and stearic acid—were characterized and comprehensively compared. The DS could be adjusted precisely, giving control over the glass transition temperature (Tg)/melting point (Tm) of the HPC-esters, yielding a toolbox to tailor HPC-ester. In a next step, nanoparticles are formed from HPC stearic acid ester and used to generate superhydrophobic surface coatings, thereby demonstrating one of the interesting potential uses of this sustainable material.
KeywordsHydroxypropyl cellulose Sustainable thermoplastics Bio based polymer Kinetic investigation Surface coating
The authors would like to thank Martina Ewald and Heike Herbert for technical support and GPC measurements. Furthermore, we would like to thank Christian Rüttiger for conducting DSC measurements, and we would like to thank Dr. A. Geissler for valuable scientific discussions. This work was funded in part by the DFG Collaborative Research Center 1194 (SFB1194 “Wechelseitige Beeinflussung von Transport- und Benetzungsvorgängen”).
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Conflict of interest
The authors declare no conflict of interest.
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