Effect of Additives on the Cloud Point Temperature of 2‑Hydroxy-3-isopropoxypropyl Starch Solutions

Temperature-responsive polymers with a lower critical solution temperature (LCST) have attracted much attention in biomedical and biotechnological fields. It is important to tune their cloud point temperature (<i>T</i>_<i>c</i>) in a broad temperature range as desired by the applications. In this study, new thermo-responsive 2-hydroxy-3-isopropoxypropyl starches (HIPS) was synthesized using Hylon V starch as raw material and isopropyl glycidyl ether as hydrophobic reagent. The phase transition behavior of HIPS and their <i>T</i>_<i>c</i> were determined by spectrophotometry. The effects of several conditions on the <i>T</i>_<i>c</i> of the HIPS were also investigated, which indicated that varying the molar substitution (MS) of HIPS can adjust <i>T</i>_<i>c</i> in a broad temperature range from 69 to 28 °C by changing the hydrophobic–hydrophilic balance of starch. The phase transition became fast and the <i>T</i>_<i>c</i> decreased with increasing polymer concentration. The effect of a series of sodium salts on the <i>T</i>_<i>c</i> of aqueous HIPS solutions was reported and the effectiveness of ions follows a trend, known as Hofmeister series. Several organic solvents were selected and the organic additives with small molecular weight can also regulate the <i>T</i>_<i>c</i> of HIPS in a certain range by changing the polymer–water interactions

Multiple Colors Output on Voile through 3D Colloidal Crystals with Robust Mechanical Properties

Distinguished from the chromatic mechanism of dyes and pigments, structural color is derived from physical interactions of visible light with structures that are periodic at the scale of the wavelength of light. Using colloidal crystals with coloring functions for fabrics has resulted in significant improvements compared with chemical colors because the structural color from colloidal crystals bears many unique and fascinating optical properties, such as vivid iridescence and nonphotobleaching. However, the poor mechanical performance of the structural color films cannot meet actual requirements because of the weak point contact of colloidal crystal particles. Herein, we demonstrate in this study the patterning on voile fabrics with high mechanical strength on account of the periodic array lock effect of polymers, and multiple structural color output was simultaneously achieved by a simple two-phase self-assembly method for printing voile fabrics with 3D colloidal crystals. The colored voile fabrics exhibit high color saturation, good mechanical stability, and multiple-color patterns printable. In addition, colloidal crystals are promising potential substitutes for organic dyes and pigments because colloidal crystals are environmentally friendly