Tuning glycerol plasticization of chitosan with boric acid.

Chitosan-based bioplastics are attractive biodegradable alternatives to petroleum-derived plastics. However, optimizing the properties of chitosan materials to fit a particular application or obtain a desired property is not a trivial feat. Here, we report the tunability of glycerol-plasticized chitosan films with the addition of boric acid.

Cooperative crosslinking in polyvinyl alcohol organogels.

Manipulating and optimizing the properties of gels is important for practical applications but can be both synthetically difficult and expensive. In this work, we report an easily tunable polyvinyl alcohol (PVA) organogel formed with boric acid (BA) and 1,4-benzenediboronic acid (1,4-BDBA) as crosslinkers. While PVA and BA alone form weak aggregations in DMSO, adding small amounts of 1,4-BDBA dramatically improves the material properties and gelation.

Polyvinyl alcohol-boronate gel for sodium hydroxide extraction.

Gels formed from commercially available polyvinyl alcohol (PVA) and 1,4-benzene diboronic acid (BdBA) in DMSO absorb NaOH efficiently from a bulk aqueous solution decreasing its pH.

Recognition and Extraction of Cesium Hydroxide and Carbonate by Using a Neutral Multitopic Ion-Pair Receptor.

Current approaches to lowering the pH of basic media rely on the addition of a proton source. An alternative approach is described herein that involves the liquid-liquid extraction-based removal of cesium salts, specifically CsOH and Cs CO , from highly basic media. A multitopic ion-pair receptor (2) is used that can recognize and extract the hydroxide and carbonate anions as their cesium salts, as confirmed by H NMR spectroscopic titrations, ICP-MS, single-crystal structural analyses, and theoretical calculations.

Molecular Recognition Under Interfacial Conditions: Calix[4]pyrrole-Based Cross-linkable Micelles for Ion Pair Extraction.

An anthracene-functionalized, long-tailed calix[4]pyrrole 1, containing both an anion-recognition site and cation-recognition functionality, has been synthesized and fully characterized. Upon ion pair complexation with FeF, receptor 1 self-assembles into multimicelles in aqueous media. This aggregation process is ascribed to a change in polarity from nonpolar to amphiphilic induced upon concurrent anion and cation complexation and permits molecular recognition-based control over chemical morphology under interfacial conditions.

Supramolecular gels made from nucleobase, nucleoside and nucleotide analogs.

Supramolecular or molecular gels are attractive for various applications, including diagnostics, tissue scaffolding and targeted drug release. Gelators derived from natural products are of particular interest for biomedical purposes, as they are generally biocompatible and stimuli-responsive. The building blocks of nucleic acids (i.

A Molecular Chaperone for G4-Quartet Hydrogels.

Thioflavin T (ThT) functions as a molecular chaperone for gelation of water by guanosine and lithium borate. Substoichiometric ThT (1 mol % relative to hydrogelator) results in faster hydrogelation as monitored by (1)H NMR and visual comparison. Vial-inversion tests and rheology show that ThT increases the stiffness of the Li(+) guanosine-borate (GB) hydrogel.

G4-quartet·M(+) borate hydrogels.

The ability to modulate the physical properties of a supramolecular hydrogel may be beneficial for biomaterial and biomedical applications. We find that guanosine (G 1), when combined with 0.5 equiv of potassium borate, forms a strong, self-supporting hydrogel with elastic moduli >10 kPa.

A G₄·K⁺ hydrogel stabilized by an anion.

Supramolecular hydrogels derived from natural products have promising applications in diagnostics, drug delivery, and tissue engineering. We studied the formation of a long-lived hydrogel made by mixing guanosine (G, 1) with 0.5 equiv of KB(OH)4.