Unique Combination of Surface Energy and Lewis Acid–Base Characteristics of Superhydrophobic Cellulose Fibers

Abstract

Cellulose fibers were first functionalized on their surface by silanization with trichloromethylsilane in an optimized gas-solid reaction, and the occurrence of the reaction was assessed using attenuated total reflection Fourier transform infrared (ATR-FTIR) spectroscopy. Then, the changes in the physicochemical surface properties of the material were thoroughly assessed using inverse gas chromatography (IGC) and X-ray photoelectron spectroscopy as surface specific tools. A very surprising combination of results was obtained: (i) the dispersive component of the surface energy was found to decrease from 42 to 14 mJ m (at 40 °C), the latter figure representing one of the lowest values ever reported (by IGC) for cellulose-based materials, and (ii) both Lewis acidic and Lewis basic characters of the fiber surface, as measured by the injection into the IGC columns of 15 different vapor probes, significantly increased with silanization. Moreover, those remarkable changes in the surface properties of the material were obtained at a low degree of silanization (as shown by ATR-FTIR). The present results may have a great impact in what concerns the application of the described type of superhydrophobic cellulose fibers for the production of new biocomposites: an unusual enhanced compatibility both with low-surface energy polymeric matrices, such as polyolefins, as well as with other types of matrices through Lewis acid-base interactions, can be predicted.

Surface characterization of polysaccharide scaffolds by inverse gas chromatography regarding application in tissue engineering

“…No previous studies of the surface of this type of materials by IGC were found in the literature. However, the γ s d values are comparable with those of chitosan or alginate alone or of other polysaccharides, such as cellulose and hemicelluloses . For instance, a 80% deacetylated chitosan presented a γ s d value of 46 mJ·m −2 at 50°C and sodium alginate showed a γ s d value of 39 mJ·m −2 at 25°C.…”

“…For instance, a 80% deacetylated chitosan presented a γ s d value of 46 mJ·m −2 at 50°C and sodium alginate showed a γ s d value of 39 mJ·m −2 at 25°C. A γ s d value of 42 mJ·m −2 was reported for bleached cellulose at 40°C and of 48 mJ·m −2 for xylan . These values reflect the major influence of the hydroxyl groups present along the chains of the PECs on the magnitude of the Lifshitz Van der Waals forces, which was determined based on measurements of the interactions of the materials with the n ‐alkanes (apolar probes).…”

“…(γ l d ) 0.5 (Figure 4). The results are presented in 36 at 40°C and of 48 mJ·m −2 for xylan. 38 These values reflect the major influence of the hydroxyl groups present along the chains of…”

Comparison of Surface Properties of Sepiolite and Palygorskite: Surface Energy and Nanoroughness

“…IGC is a very accurate and versatile characterization tool. In particular, IGC can overcome the contact angle measurement limitations in the analysis of porous, rough, and heterogeneous surfaces [ 6 , 7 , 9 ].…”

Novel Low-Temperature Chemical Vapor Deposition of Hydrothermal Delignified Wood for Hydrophobic Property

“…The low-temperature chemical vapor deposition (CVD) was utilized to the hydrophobic modification for the cellulose-based materials and wood composite materials. For example, Gamelas et al [ 24 ] implemented fast CVD to fabricate hydrophobic pulp by using trichloromethylsilane vapor silanization. Although this method could offer the hydrophobic function to the modified surfaces by the salinization treatment, the size of cellulose fibers was in the nanometer range.…”