Hydrophilic to hydrophobic: Ultrafast conversion of cellulose nanofibrils by cold plasma fluorination

Permanent hydrophobic coating of chitosan/cellulose nanocrystals composite film by cold plasma processing

“…The closed reactor system offers the possibility of gas capturing and recycling, preventing harmful gas exhaust into the environment [24,25]. Furthermore, the possibility of scale-up and utilization of the same assembly system for tailoring the materials surface properties with various dopants (nitrogen, oxygen, sulfur, or fluorine) highlights the industrial applicability of the technique [26,27,28].…”

“…Slight increase in hydrophobicity, water contact angle rose from initial 13°to 23°, was achieved with alkane vapor plasma technique [32]. On the example of cellulose textiles and films, it has already been demonstrated that plasma using fluorinated compounds as a carrier gas successfully modifies surface and enhances its hydrophobic character [33,34,35,36,28].…”

Cellulose Nanopaper: Fabrication, Functionalization, and Applications

“…In order to address this problem, various hydrophobic modification strategies have been proposed, such as esterification, polymer grafting, plasma fluorination, among others. For example, Oberlintner and co-workers reported an ultrafast approach to improve the CNP surface hydrophobicity by cold plasma fluorination [ 173 ]. Specifically, the CNP sample was exposed to CF 4 plasma for less than 10 s, and the contact angle of the treated CNP significantly increased from 46° to 130° after only 30 s of plasma processing.…”

Sulfonated Polybenzothiazoles Containing Hexafluoroisopropyl Units for Proton Exchange Membrane Fuel Cells

“…Additionally, a high degree of sulfonation is imperative for sulfonated aromatic polymer-based PEMs to achieve a proton conductivity comparable to that of perfluorinated PEMs. Nevertheless, polymers with a high degree of sulfonation often overswell, which will result in a decrease in dimensional stability. − Therefore, an improved hydrophilic and hydrophobic phase separation structure is often used to strengthen the dimensional stability of high sulfonated polymer PEMs. , Due to the self-assembly capacity of fluorine atoms, their incorporation into the polymer skeleton is an effective way to regulate the separation of hydrophilic/hydrophobic phases. − Incorporation of fluorine into the polymer also improves the polymer processability . As a hydrophobic functional group, hexafluoroisopropylide is expected to have three effects upon incorporation into the polymer backbone: (1) increased flexibility of the main chain, resulting in improvement in polymer solubility, (2) formation of ion channels to improve the proton conduction ability, and (3) increased hydrophobicity of the polymer, providing a more obvious phase separation and improving the dimensional stability of the membrane. ,− …”