Attension theta lite

Moisture was determined according to Gontard et al. [35 (link)], where film samples (2 cm × 2 cm) were oven dried (Fanem, 515, Sao Paulo, Brazil) at 105 °C for 24 h and the moisture content was determined considering the samples mass loss.
To determine solubility, samples (2 × 2 cm) were dried at 105 °C (24 h) and transferred to beakers with 50 mL of distilled water, submitted to shaking (100 rpm) in a Shaker incubator (Marconi, MA 420, Piracicaba, Brazil) for 24 h [35 (link)]. Subsequently, the samples were again oven dried (Fanem, 515, Sao Paulo, Brazil) at 105 °C for 24 h and the soluble material was determined according to Equation (2): $Solubility(\%)=\left(\frac{m_i-m_f}{m_i}\right)$
where: $m_i$ is the (g) sample initial dry mass and $m_f$ is the (g) sample final dry mass.
The contact angle was determined using a tensiometer (Attension Theta Lite, KSV Instruments, Filderstadt, Germany) according to Abdollahi et al. [36 (link)], which consisted of fixing the film sample (2 × 3 cm) to the base of the equipment and depositing a drop of ultrapure water (5 µL) onto the film surface. Images were recorded after 10 s and digital images were analyzed using the Attension Theta Lite software (Version 4.1.9.8).

The water contact angle (WCA) with the air-side surface of the films was determined using an optical tensiometer (Attension Theta lite, KSV Instruments, Helsinki, Finland) equipped with OneAttension image analysis software (Version 4.1.9.8). Film samples were fixed to the equipment support and a drop of Milli-Q water was deposited on the film’s air-side surfaces using a precision syringe. Images were recorded each second for 60 s, and the WCA values were obtained in the chosen time of 15 s [12 (link)].

The film water contact angle (WCA) was measured using an optical tensiometer (Attension Theta Lite, KSV Instruments, Helsinki, Uusimaa, Finland), as indicated in the ASTM D7334 standard method [32 ]. The samples (20 mm × 30 mm) were attached to the equipment support, and then a drop of Milli-Q water (5 µL) was dripped onto the air-side surface of the film with a precision syringe. The samples were photographed for 40 s. The sessile drop method at 30 s was used to obtain the contact angle with the Attension Theta software (Version 4.1.9.8).