Thermo-sensitive composite microspheres incorporating cellulose nanocrystals for regulated drug release kinetics.

Thermo-sensitive composite microspheres (TPCP) were developed to achieve the on-demand release of drugs. The TPCP microspheres were synthesized using Oil-in-Water (O/W) emulsion evaporation technique and then impregnated with thermo-sensitive polyethylene glycol (PEG). The addition of cellulose nanocrystals (CNCs) significantly enhance thermal stability, crystallization ability, and surface hydrophilicity of TPCP microspheres due to heterogeneous nucleation effect and hydrogen bonding interaction, resulting in stable microsphere structure. The thermal degradation temperature (Tmax) increased by 13.8 °C, and the crystallinity improved by 20.9 % for 10 % TPCP. The thermo-sensitive composite microspheres showed the regulated cumulative release according to in vitro human physiological temperature changes. Besides, four release kinetics and possible release mechanism of TPCP microspheres were provided. Such thermo-responsive composite microspheres with control microsphere sizes and high encapsulation rate may have the potential to the development of on-demand and advanced controlled-release delivery systems.

Magnetic cellulose nanocrystals hybrids reinforced phase change fiber composites with highly thermal energy storage efficiencies.

The intrinsic intermittence of solar energy raises the necessity for thermal energy storage (TES) systems to balance the contradiction between energy supply and demand energy. This work experimentally provides solid-liquid phase change materials (PCMs) with sufficient storage capacity and discharging rate to offer heating for agriculture products by enhancing heat transfer in phase change fiber composites (PCF). To achieve this, we prepared dipole responsive magnetic/solar-driven PCF composites reinforced with magnetic cellulose nanocrystals hybrids (MCNC). The obtained PCF/MCNC-5% showed excellent magnetic property with a saturation magnetization (MS) value of 1.3 emu/g and effective latent heat phase change enthalpies of 69.2 ± 3.5 J/g - 83.1 ± 4.2 J/g. More importantly, PCF/MCNC-5% showed robust high magnetic to thermal energy storage efficiency of 32.5 % and solar light accelerated energy storage efficiency of 58.5 %. These advantages make the PCF composites promising and more desirable for drying and preservation of the fruits and other agriculture products.