Semicrystalline polymers are often used as macromolecular excipients in active pharmaceutical ingredient (API)‐delivery systems. In such systems, the morphological structure and crystalline characteristics of the excipient have a direct impact upon the drug‐delivery rate. In this study, polycaprolactone (PCL)‐based microspheres prepared via melt‐printing were loaded with 10, 30, and 50% ibuprofen (IBU). In vitro release studies showed that, for a constant amount of IBU, the API was released fastest from the 30%‐loaded microspheres, followed by the 50%‐ and 10%‐loaded microspheres. The discrepancy in these release rates was investigated using scanning electron microscopy, differential scanning calorimetry, X‐ray diffraction, and thermodynamic analyses, revealing the complex morphological and crystalline interrelationships of PCL and IBU. Although it is generally accepted that the degree of crystallinity of the excipient is the main factor controlling the release of the API, we found that the crystallite size of the small‐molecule API is of primary importance. Moreover, these factors, which are controllable via the parameters used in melt‐based preparation, can be exploited to tune drug‐release rates. © 2019 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2019, 136, 47227.

Applying direct growth and deposition of optical surfaces holds great promise for the advancement of future nanophotonic technologies. Here, we report on a chemical vapor deposition (CVD) technique for depositing amorphous selenium (a-Se) spheres by desorption of selenium from Bi2Se3 and re-adsorption on the substrate. We utilize this process to grow scalable, large area Se spheres on several substrates and characterize their Mie-resonant response in the mid-infrared (MIR) spectral range. We demonstrate size-tunable Mie resonances spanning the 2–16 μm spectral range for single isolated resonators and large area ensembles. We further demonstrate strong absorption dips of up to 90% in ensembles of particles in a broad MIR range. Finally, we show that ultra-high-Q resonances arise in the case where Se Mie-resonators are coupled to low-loss epsilon-near-zero (ENZ) substrates. These findings demonstrate the enabling potential of amorphous Selenium as a versatile and tunable nanophotonic material that may open up avenues for on-chip MIR spectroscopy, chemical sensing, spectral imaging, and large area metasurface fabrication.

No abstract