Engineered Ionene/PNIPAM Hybrid Dual-Response Material Generating Tunable and Unique Optical Modes for Adaptive Solar Transmittance Modulation.

A hybrid smart window exhibiting dual chromic response properties based on an ionene/polymer material is successfully engineered. Thermochromic poly(N-isopropylacrylamide) is integrated with an electrochromic viologen-tethered ionene, also acting as an electrolyte, to produce a smart window that can adaptively control solar visible light transmittance in response to multiple stimuli. This new blend allows the formation of unique reversible optical states, namely, "clear", "amber", "cloudy", and "grainy" states, which are passively triggered by environmental temperature and actively induced by external potential or simultaneously by both. This hybrid material shows tunability in terms of its electrochemical and optical properties, switching kinetics, and coloration efficiency and can also achieve a nearly absolute zero-transmissive state. With the material's excellent solubility and film-forming ability, the smart device can be fabricated with much flexibility and ease. Finally, this device has an all-in-one layer configuration, creating a more compact and simplified design. With all these properties combined, the development of a next-generation multifunctional smart window device, which can efficiently control incoming solar light for energy-saving in buildings and also provide visual comfort, is possible.

Characterization of structure, physico-chemical properties and diffusion behavior of Ca-Alginate gel beads prepared by different gelation methods.

Ca-Alginate beads were prepared with either external or internal calcium sources by dripping technique. It was found that beads synthesized with internal calcium source had a looser structure and bigger pore size than those produced with external calcium source. Consequently, a faster diffusion rate of Vitamin B12 (VB12) within the beads with an internal calcium source was observed. Furthermore, the concentration of calcium ion, ionic strength and pH of the external gel beads formation solution were investigated. Results showed that (a) the concentration of the calcium ion was found to be the determining factor in the gel formation phenomenon; (b) the weight and volume losses are in effect due to water removal; (c) NaCl acts as a competitor with calcium and a screen in the electrostatic repulsion; and (d) the pH controls the gel formation process by regulating the dissociation of alginate and the complexation of the calcium cations. These results are keys to understanding the behavior and performance of beads in their utilization medium.