*3.4. Surface Wettability of Silane-coated cellulose aerogel*

Water contact angle measurements were also carried out on the uncoated and coated aerogel to study their surface wettability. The uncoated CA sample absorbed the distilled water droplet immediately in the test so no measurable contact angle was recorded. In contrast, high contact angles are observed for the MEMO silane-coated aerogel, as shown in Figure 8, proving the hydrophobicity of the material.

**Figure 8.** Measurements of water contact angle of cellulose aerogels after different coating processes.

Table 2 shows the improvement of the water contact angle of cellulose aerogels from 114.1 ± 5.26◦ to 132.3 ± 4.68◦ when the silanization time was increased from 6 to 12 h, indicating the high hydrophobicity of the obtained SCA. No increase in water contact angle was observed with further extended reaction times.


**Table 2.** Change of coated cellulose aerogel's water contact angle with silianation time.
