Thermochromic windows can reduce temperature changes, thereby reducing electricity consumption. Traditional hydrogel-based thermochromic windows suffer from volatilization and freezing, reducing their utility as protective enclosures for display cases. Here, we present a dual-layer organohydrogel system (DG), consisting of thermochromic organohydrogels that provide both heat shielding and heat retention for smart windows. The cononsolvency caused by polyethylene glycol (PEG) is introduced to sharply reduce the thermochromic temperature to below 10 °C for applicability in thermostatically controlled display windows by strengthening hydrogen bonding between mediums and affecting the interaction between copolymer chains and water molecules. PEG imparts antifreeze, liquid retention, and regenerative qualities to DG, enhancing its stability and recyclability. Organohydrogels exhibit over 90 % light transmittance, obstruct 99.17 % of solar heat, and scatter 23.14 % of mid-infrared light. Within 24 h, DG conserves energy at high rates of 37.22 % and 27.13 % in hot and cold settings, respectively. Thus, aims of DG are to maintain a stable temperature within thermostatic display cases and promoting emissions mitigation.
Despite the fact that the observation of cononsolvency was reported as early as four decades ago, its phase-transition mechanism is still under debate. In this work, we provided a comprehensive study of the phase behaviors of poly(N-isopropylacrylamide) (PNiPAAm) in sulfoxide or sulfone aqueous solutions. We observed a sharp collapse transition of PNiPAAm brushes in sulfoxide but not in sulfone aqueous solutions by equilibrium measurements of in situ spectroscopic ellipsometry. We found that the hydrogen-bond formation between sulfoxide oxygens and amide hydrogens of the polymer chains plays a critical role in regulating the cononsolvency of PNiPAAm. We have extended the concept of preferential adsorption by taking into account hydrophobic interactions between cosolvent molecules, which are adsorbed on the polymer by hydrogen bonds. This can explain the experimental observations of PNiPAAm brushes in these solvent mixtures and sheds light on understanding the phase behaviors of polymer solutions where hydrogen bonds and hydrophobic interaction play a critical role. Our results can also be of interest for the liquid–liquid phase separation in the living cell where the condensation of proteins bound to large biomacromolecules plays an essential role.
Jingjie Hou,Yujia Liu,Yunze Ma,Huajiang Zhang,Ning Xia,Hanyu Li,Zhongjiang Wang,Ahmed M. Rayan,Mohamed Ghamry,Taha Ahmed Mohamed
Although protein-polysaccharide complexes with different phase behaviors all show potential for stabilizing high internal phase Pickering emulsions (HIPPEs), it is not clarified which aggregation state is more stable and age-friendly. In this study, we investigated and compared the stability and age friendliness of HIPPEs stabilized with egg yolk and carboxymethyl cellulose (EYCMC) in different phase behaviors. The results revealed differences in particle size, aggregation state, charge potential, and stability of secondary and tertiary structures of EYCMC. The behavior of EYCMC at the oil-water interface was mainly divided into three phases: rapid diffusion, permeation, and reorganization. The electrostatic interaction, kinetic hindrance, and depletion attraction were the mechanisms primarily involved in stabilizing HIPPEs by EYCMC. Rheological analysis results indicated that HIPPEs had excellent viscoelasticity, structural recovery properties and yield stress. HIPPEs were used in 3D printing, electronic nose testing, IDDSI testing and in vitro digestive simulations for the elderly, demonstrating a fine appearance, safe consumption and bioaccessibility of β-carotene. Soluble complexes showed the best stability and age friendliness compared to other aggregated forms. This study serves as a foundational source of information for developing innovative foods utilizing HIPPEs.
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