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The present paper reports on the preparation and characterization of potential edible packaging films based on the combination of chitosan and Piper betle Linn. leaf extract (PBLLE). The incorporation of PBLLE was found to improve important characteristics of the chitosan film, making it ideally suitable for active packaging applications. In particular, the blend films exhibited very strong inhibitory activities against both gram‐negative and gram‐positive bacteria such as Bacillus subtilis and Salmonella Typhimurium. Moreover, IC50 values of the blend films were recorded at low levels (10.63‐ 22.81 μg/mL) in the PBLLE range of 1–3% v/v. Both antimicrobial and antioxidant activities of the blend films increased with increasing incorporated PBLLE content (from 1 to 3% v/v) taking into account the activities of polyphenolic compounds contained in the extract. Compared to the pure chitosan film, a significantly lower swelling degree, higher resistance to water vapor permeation and desired flexibility were recorded for the films with sufficient extract content. Interestingly, no considerable difference in the thermal stability of the pure chitosan and the blend films was detected in thermal analysis. In addition, effects of PBLLE on other mechanical and optical properties of the blend films were also examined in detail.

We conducted a high-throughput investigation of the fundamental properties of (Mg,Hf)AlN thin films (0 < x < 0.24) aiming for developing high-performance AlN-based piezoelectric materials. For the high-throughput investigation, we prepared composition-gradient (Mg,Hf)AlN films grown on a Si(100) substrate at 600 °C by cosputtering AlN and MgHf targets. To measure the properties of the various compositions at different positions within a single sample, we used characterization techniques with spatial resolution. X-ray diffraction (XRD) with a beam spot diameter of 1.0 mm verified that Mg and Hf had substituted into the Al sites and caused an elongation of the c-axis of AlN from 5.00 Å for x = 0 to 5.11 Å for x = 0.24. In addition, the uniaxial crystal orientation and high crystallinity required for piezoelectric materials to be used as application devices were confirmed. The piezoelectric response microscope indicated that this c-axis elongation increased the piezoelectric coefficient almost linearly from 1.48 pm/V for x = 0 to 5.19 pm/V for x = 0.24. The dielectric constants of (Mg,Hf)AlN were investigated using parallel plate capacitor structures with ∼0.07 mm electrodes and showed a slight increase by substitution. These results verified that (Mg,Hf)AlN is a promising material for piezoelectric-based application devices, especially for vibrational energy harvesters.

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