Hydrophobic curcumin in temulawak extract and hydrophilic betacyanin in red dragon fruit extract are high-value bioactive compounds with extensive applications in functional food. In this study, these extracts were encapsulated in water-in-oil-in-water (w/o/w) nanoemulsions as a delivery system using a two-step high-energy emulsification method. PGPR and Span 20 were used as lipophilic emulsifiers for the primary w/o emulsion. The most stable w/o/w formulation with the least oil phase separation of 5% v/v consisted of w/o emulsion (15% w/w) and Tween 80 (1.5% w/w) as hydrophilic emulsifier. The formulation was characterized by a 189-nm mean droplet diameter, 0.16 polydispersity index, and –32 mV zeta potential. The freeze–thaw stability may be attributed to the combination of low w/o emulsion content and high Tween 80 concentration in the outer water phase of the w/o/w nanoemulsions used in this study. The IC₅₀ values of the nanoemulsion and the red dragon fruit extract were similar. It means that the higher concentration of curcumin in the nanoemulsions and the lower IC₅₀ value of temulawak extract ensured sufficient antioxidant activities of the w/o/w nanoemulsions.

We present a facile method to produce silica nanoparticles as a superhydrophobic material which has been successfully synthesized by mechanical milling and the sol–gel method. The powder obtained was characterized using scanning electronic microscopy, X-Ray Diffraction, particle size distribution, and zeta potential. The effects of alcohol solvents on synthesis, such as on particle size, particle size distribution, and zeta potential, were examined thoroughly. To evaluate the surface modification of silica nanoparticles from hydrophilic to hydrophobic properties, IR spectra was applied. Surface modification was conducted prior to the evaluation of the superhydrophobic properties of silica nanoparticles on the glass substrate. In this study, silica nanoparticles in the ethanol solvent achieved optimum results with a particle size of 170.3 ± 14.3 nm and the highest zeta potential of −50.4 ± 0.3 mV, which is the best superhydrophobic effect on the glass substrate. In addition, the superhydrophobic effect of the silica nanoparticles was also applied to the bitumen, as both coating and mixing with the water contact angle was increased to 149.2° and 148.1° compared to the bitumen without silica nanoparticles. Due to their simplicity and low-cost, modified silica nanoparticles show great potential for industrial applications as superhydrophobic material on the bitumen.