Design and Properties of Novel Hydrophobic Natural Tea Saponin and Its Organogels.

It was first discovered that the excellent gelation ability of tea saponin can be obtained by introducing long-chain alkyl groups of dodecanoyl chloride into the glycosyl portion with direct esterification. The modified dodecanoyl chloride-tea saponin (DC-TS) was successfully synthesized and characterized with NMR, MS, and FT-IR. The tests showed that the long-chain alkyl group was successfully introduced. Combined with SEM and X-ray diffraction patterns, we found that the stable lamellar shape gels of DC-TS were formed in a variety of solvents. More interestingly, organogel was also obtained by adjusting good solvent and poor solvent as mixed solvent. It is worth noting that the driving force of organogels is the combination of hydrogen bonding and the hydrophobic interaction of the introduced alkyl chains with the rigid backbone of pentacyclic triterpenes. The modified tea saponin, a natural green surfactant, was discovered to have gelation properties, which has broadened tea saponin's scope of application and made it more promising.

Design and Properties of Natural Rosin-Based Phosphoester Functional Surfactants.

As an important forestry biomass resource, rosin has a wide range of applications in medicine, adhesives, surfactants and other fields. Using natural dehydroabietic acid as a raw material, dehydroabietic acid-based phosphorus monoester (DPM) and diester (DPD) surfactants were designed and synthesized. The chemical structures and self-assembly properties were characterized by FT-IR, NMR and TEM, and the effects of pH on critical micelle concentration, γCMC, emulsifying properties, foam properties and micelle morphology were studied. The results showed that the CMC, γCMC value and aggregate morphology had certain pH responsiveness. The γCMC value under acidic conditions was smaller than γCMC under alkaline conditions, and the foaming performance and foam stability under acidic conditions were better than those under alkaline conditions. TEM micelle morphology studies have shown that DPM and DPD surfactants can self-assemble into rod-shaped and spherical micelle morphologies with a pH change in an aqueous solution. At the same pH, the foaming and emulsification properties of DPD were better than those of DPM. The best foaming and emulsification ability of DPD were 11.8 mL and 175 s, respectively. At the same time, the foaming ability of DPD is also affected by pH. DPD has excellent foaming properties in acidic conditions, but these disappeared in neutral conditions.

Molecular Design, Supramolecular Assembly, and Excellent Dye Adsorption Capacity of Natural Rigid Dehydroabietic Acid-Tailored Amide Organogelators.

It is very appealing to synthesize functional soft materials from natural and abundant plant diterpenes because they have conformationally rigid and chiral properties. Herein, dehydroabietic-based monoamide (DA-1) and diamide (DA-2) were designed by introducing device interactions, π-π stacking and hydrogen bonding, with an aromatic group, C═O, and N-H. DA-1 and DA-2 can be gelled in a mixed solvent and a single solvent, respectively. Several novel supramolecular organic gels including highly entangled three-dimensional networks composed of rods or fibers were constructed. Interestingly, DA-2 forms a helical structure that is right-handed under the cooperative control of the solvent and the rigid structure of rosin. Gel formation was primarily driven by hydrogen bonding, π-π stacking, and van der Waals force. Combined with Gaussian calculation and X-ray diffraction (XRD), we established pack patterns for each system, revealing the roles played by rosin and amide groups. Moreover, the carbon tetrachloride gel of DA-2 can effectively remove Congo red in an aqueous solution, and the removal rate can reach 98.4%. This research explores an efficient organic gel for adsorbing Congo red dye with the secretions of pine trees.

Wood-inspired nanocellulose aerogel adsorbents with excellent selective pollutants capture, superfast adsorption, and easy regeneration.

Heavy metal ions can cause a series of hazards to environment and humans. Herein, we developed a wood-inspired nanocellulose aerogel adsorbent with excellent selective capability, superfast adsorption, and easy regeneration. The premise for the design is that the biomimetic honeycomb architecture and specific covalent bonding networks can provide the adsorbent with structural and mechanical integrity yet superfast removal of target contaminants. The as-obtained adsorbent showed the maximum adsorption capacity for Pb(II), Cu(II), Zn(II), Cd(II), and Mn(II) of 571 mg g-1, 462 mg g-1, 361 mg g-1, 263 mg g-1, and 208 mg g-1, respectively. The adsorbent could remove Pb(II) species with super-rapid speed (87% and 100% of its equilibrium uptake in 2 min and 10 min, respectively). Furthermore, the adsorption isotherm and kinetics models were in accord with the Langmuir and pseudo-second-order models, indicating that the adsorption behavior was dominated by monolayer chemisorption. The aerogel adsorbent had better affinity for Pb(II) than other coexisting ions in wastewater and could be regenerated for at least five cycles. Such a wood-inspired aerogel adsorbent holds great potential in the application of contaminant cleaning.