10 research outputs found
Synthesis of pH-responsive N-acetyl-cysteine modified starch derivatives for oral delivery
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><sub><i>c</i></sub>) 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><sub><i>c</i></sub> were
determined by spectrophotometry. The effects of several conditions
on the <i>T</i><sub><i>c</i></sub> of the HIPS
were also investigated, which indicated that varying the molar substitution
(MS) of HIPS can adjust <i>T</i><sub><i>c</i></sub> 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><sub><i>c</i></sub> decreased with increasing polymer concentration. The effect of a
series of sodium salts on the <i>T</i><sub><i>c</i></sub> 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><sub><i>c</i></sub> of HIPS in a certain range by changing the polymer–water
interactions
Polysulfide nanoparticles-reduced graphene oxide composite aerogel for efficient solar-driven water purification
Along with the environmental pollution, the scarcity of clean water seriously threatens the sustainable development of human society. Recently, the rapid development of solar evaporators has injected new vitality into the field of water purification. However, the industry faces a considerable challenge of achieving comprehensive purification of ions, especially the efficient removal of mercury ions. In this work, we introduce an ideal mercury-removal platform based on facilely and cost-effectively synthesized polysulfide nanoparticles (PSNs). Further development of PSN-functionalized reduced graphene oxide (PSN-rGO) aerogel evaporator results in achieving a high evaporation rate of 1.55 kg m−2 h−1 with energy efficiency of 90.8% under 1 sun. With the merits of interconnected porous structure and adsorption ability, the photothermal aerogel presents overall purification of heavy metal ions from wastewater. During solar desalination, salt ions can be rejected with long-term stability. Compared with traditional water purification technologies, this highly efficient solar evaporator provides a new practical method to utilize clean energy for clean water production
Synthesis and characterization of starch ether/alginate hydrogels with reversible and tunable thermoresponsive properties
A thermoresponsive hydrogel that was composed of 2-hydroxy-3-isopropoxypropyl starch (HIPS) and alginate was synthesized via cross-linking with hybrid crosslinkers including ethylene glycol diglycidyl ether (EDGE) and calcium chloride (CaCl _2 ). Attenuated total reflection infrared spectroscopy (ATR-IR), thermogravimetric analysis (TGA) and derivative thermogravimetry (DTG) were used to confirm that cross-linking occurred. The porous architecture of the HIPS/SA composite hydrogels was investigated using scanning electron microscopy (SEM). Composite hydrogels had a tunable volume phase transition temperature (VPTT) that was in the range from 29.4 to 40.2 °C and resulted from changes in the compositions (HIPS concentration from 5.5 to 7.5 wt%). It was also found that the presence of NaCl (0 to 20 g l ^−1 ) or organic solvents (alcohols, 0 to 50 g l ^−1 ) in aqueous medium changed the VPTT of the composite hydrogels; also, the VPTT decreased as the concentration of NaCl or organic solvents increased. Additionally, alcohols that have long carbon chains (isopropanol > ethanol > methanol) exhibited a more significant effect on the VPTT of hydrogel. The hydrogel could shed and absorb most of the water in a very short time and demonstrate a stable reversible swelling-deswelling property after 5 swelling-deswelling cycles
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