Oca40

The morphologies of particles were characterized on a scanning electron microscope (SEM, Hitachi, Tokyo, Japan, S-4800, 20 kV) and the feature sizes of the particles were obtained by measuring at least 200 particles. The SEM samples were sputtered with Au to improve the conductivity. The hydrophobic property of particulate coatings was analyzed with an OCA (Optical Contact Angle) meter (Dataphysics, OCA40, Filderstadt, Germany) via the sessile drop method using the Laplace–Young fitting algorithm. The volume of the water drop was 3 μL and the dispensing speed was 0.5 μL/s. The contact angle values were determined from the average of three measurements at different positions. TGA curves were obtained with a Mettler TGA 1100 SF, and FTIR spectra were collected with ABB FTLA 2000-104 (ABB, Zurich, Switzerland).

Scanning electron microscopy (SEM, SU8010, HITACHI, Hitachi, Japan) was performed to observe the chemical element of the TiO₂@CB/CF. Fourier-transform infrared (FTIR, NEXUS-670, GNI, Woburn, MA, USA) spectra were used at room temperature from 400 to 4000 cm⁻¹. An ultraviolet-visible-near-infrared spectrometer (UV-vis-NIR, UV 3600, Shimadzu Scientific Instruments, Kyoto, Japan) was used to test the total transmittance (T) and reflectance (R) of a sample. The water contact angles of different materials were obtained with a goniometer (OCA40, Dataphysics, Filderstadt, Germany) using 2 μL of water at ambient temperature.

The contact angles of the OSAS, SP-EGCG, and OSAS-SP-EGCG complexes were determined using an OCA 40 (Dataphysics Instruments GmbH, Stuttgart, Germany) following the method described by Dai et al. (25 (link)). First, the dried sample powders were pressed to obtain particle-based tablets (13 mm diameter and 2 mm thickness). A drop of pure water (5 μL) was then lightly dripped onto the surface of the tablets. After equilibrium was reached, the droplet was photographed, and the profile of the droplet was automatically fitted to the Laplace-Young equation using software to acquire the contact angle. Measurements were performed at least three times.

Static contact angles (SCA) were attained with a CAM200 contact angle meter (KSV instruments Ltd, Finland). A 10 μL drop was deposited on the capsule-coated glass-slide using a micropipette and images were recorded and analysed by the software (OneAttension, Biolin Scientific, Sweden). The SCA was measured at five different positions on the surface, and in each position more than 20 images were processed.
The surface tensions of the liquids used in the present study were measured with the same instrument and were 72.1 mN m⁻¹ MilliQ-water, 48.4 mN m⁻¹ ethylene glycol, 33.4 mN m⁻¹ olive oil and 27.3 mN m⁻¹ hexadecane.
Methylene Blue and Oil Red O was used to color the water blue and hexadecane red in MOVIE_2, MOVIE_3, MOVIE_4 and Fig. 3E.
Roll-off angles (RAs) were measured with a Dataphysics OCA 40 instrument equipped with a tilting stage. A 10 µL droplet was dispensed on the horizontal surface with a syringe needle after which the sample was tilted at a speed of 0.3° s⁻¹. The roll-off angle was recorded as the tilt angle when the droplet was set in motion (see MOVIE_1.avi). The roll-off angle was measured at 8 different positions on the surface.
All measurements were performed at 23 °C and 50% RH.