Surface Modification of a Regenerated Cellulose Film Using Low-Pressure Plasma Treatment with Various Reactive Gases

Abstract

There is a growing interest in the fabrication of membranes and packaging materials from natural resources for a sustainable society. A regenerated cellulose (RC) film composed solely of cellulose has outstanding advantages including biodegradability, transparency, mechanical strength, and thermal stability. To expand the application of the RC film, various surface modification methods have been proposed. However, conventional chemical methods have disadvantages such as environmental burden and difficulty in controlling the reaction. In this work, low-pressure plasma treatment, a green, solvent-free, and easily controllable approach, was performed for surface modification of the RC film. The effects of three different plasma species (O2, N2, and CF4) and treatment conditions on the surface properties of RC films were investigated based on water contact angle measurements, chemical composition analysis, and surface topography. O2 and N2 plasma treatment slightly enhanced the surface wettability of RC films due to the etching by the plasma reactive species and the formation of new hydrophilic functional groups. In CF4 plasma treatments, the hydrophobic surface with a contact angle of 120.6° was obtained in a short treatment time (60 s) owing to the deposition of fluorocarbon groups on the surface. However, the treated surface in a longer reaction time resulted in increased wettability due to the diffusion and degradation of fluorine-containing bonds. The new insights could be valuable for further studies of surface modification and functionalization of RC films.

Stable Surface Modification by Cold Atmospheric-Pressure Plasma: Comparative Study on Cellulose-Based and Synthetic Polymers

“…The increase in O/C during extended plasma treatment is attributed to a higher proportion of carbon with a single oxygen bond, C3, along with a reduction in the quantity of carbon bonded to fluorine, C7. It is worth noting that the degradation of fluorine-containing bonds due to plasma exposure has been reported in other papers, as in [51].…”

Recent Progress in Cellulose Hydrophobization by Gaseous Plasma Treatments

“…Extensive desorption of water may explain some non-expected results, for example, the highly hydrophilic surface finish obtained after prolonged treatment with CF 4 plasma. Namely, Kawano et al [ 26 ] reported optimal hydrophobicity (WCA 120°) after treating a cellulose film for a minute, but the WCA dropped to as low as 25° after treating the same material for 4 min.…”

“…Kawano et al [ 26 ] also utilized CF 4 plasma to coat cellulose with a thin film of fluorinated carbon. They used regenerated cellulose to synthesize thin films.…”

“… The static water contact angle on cellulose surfaces after deposition of a hydrophobic film by plasma polymerization. ( a ) Versus the pressure, and ( b ) versus the plasma treatment time [ 16 , 17 , 19 , 22 , 23 , 24 , 25 , 26 , 27 ]. …”

Role of plasma process gas on permeate flux augmentation of cellulose nitrate membrane for mud water treatment

“…The investigation into the effects of plasma treatment on different types of the membranes such as polyacrylonitrile 23 , cellulose nitrate 24 , polyethersulfone 25 , polyacrylonitrile copolymer 26 , polysulfone 27 , polypropylene 28 , regenerated cellulose 29 , cellulose acetate composite polyion complex 30 , polycarbonate 31 , Aromatic Polyamide 32 , polytetrafluoroethylene 33 has been reported by different researchers. The study reveals the distinct surface modifications as a result of the incorporation of functional groups into the plasma-treated membrane, which alter the antifouling and permeability properties of the membrane.…”