Cellulose model surfaces-simplified preparation by spin coating and characterization by X-ray photoelectron spectroscopy, infrared spectroscopy, and atomic force microscopy

Spin coating is introduced as a simplified method to prepare model surfaces of cellulose. Prior to spin coating, trimethylsilyl cellulose (TMSC), a nonpolar derivative of cellulose, is synthesized in order to dissolve the otherwise immiscible cellulose. After the spin coating deposition of TMSC on an untreated silicon or gold substrate, the TMSC layer is subjected to vapor phase acid hydrolysis, which regenerates it back to cellulose. X-ray photoelectron spectroscopy (XPS) and attenuated total reflectance infrared spectroscopy (ATR-IR) revealed the films' chemical structure to be similar to pure cellulose. Spin coating parameters such as spinning speed, concentration of the coating solution, and nature of the solvent were varied to obtain diversity in morphology and thickness of the films. The optimal spin coating parameters resulted in a cellulose film with 20 nm thickness and 10% roughness, determined by atomic force microscopy (AFM). Preliminary experiments with modifying the chemistry and varying the water content of the films were also conducted.