From Surfactants to Viscoelastic Capsules

Angelis, Gaia De; Gray, Natascha; Lutz‐Bueno, Viviane; Amstad, Esther

doi:10.1002/admi.202202450

Cited by 5 publications

(8 citation statements)

References 48 publications

(53 reference statements)

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“…Even thinner shells, 11 nm, are obtained if surfactants are crosslinked with Fe 3+ . This shell thickness is very similar to the calculated length of a fully stretched surfactant, which is 9 nm, suggesting that these surfactants indeed form a monolayer that is ionically crosslinked …”

Section: Resultssupporting

confidence: 72%

“…We quantify the shell thickness based on the analysis of the scattering intensity ( I ) as a function of the scattering vector ( q ) (Figure a). Because the diameters of the emulsion drops are larger than the maximum dimension that SANS can probe, which is 300 nm, we observe the shells as infinite planes that can be modeled with a thin disk form factor P ( q ). − Surprisingly, based on the fittings, the q -value where the I ( q ) slope deviates from −2 suggests that pure surfactants form thick shells of around 50 nm, as indicated with an arrow in Figure a. These results indicate that surfactants form clusters and poorly defined interfaces, as schematically shown in Figure b.…”

Section: Resultsmentioning

confidence: 83%

“…To enable ionic crosslinking, we couple two gallols to the two amines that are presented at the end of the hydrophilic block, as shown in Figure 1b. 36 Fourier transform infrared (FTIR) spectroscopy and nuclear magnetic resonance (NMR) spectroscopy reveal the successful coupling of pyrogallol functionalized Jeffamine to the perfluorinated block, indicating the successful synthesis of the pyrogallol functionalized surfactant, as shown in Figure S1 and S2 and detailed in the Supporting Information. To form viscoelastic membranes, we dissolve the surfactant in a perfluorinated oil, HFE7100, and gently add an aqueous phase containing the appropriate crosslinking ions on top of the oil phase, as shown in Figure 1a.…”

Section: Resultsmentioning

confidence: 96%

“…The surfactant was synthesized as previously reported . Briefly, the carboxylic acid functionality on the gallic acid molecule was activated via NHS/DCC chemistry and then reacted with 0.5 mol equivalents of 1,3-diaminopropan-2-ol in ethyl acetate.…”

Section: Materials and Methodsmentioning

confidence: 99%

“…When focusing on the interfacial properties, the emulsion core was composed of pure water. More details about the fitting can be found in ref .…”

Section: Materials and Methodsmentioning

confidence: 99%

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Rheological Properties of Ionically Crosslinked Viscoelastic 2D Films vs. Corresponding 3D Bulk Hydrogels

Angelis

Lutz‐Bueno

Amstad

2023

ACS Appl. Mater. Interfaces

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Ionically crosslinked hydrogels containing metal coordination motifs have piqued the interest of researchers in recent decades due to their self-healing and adhesive properties. In particular, catechol-functionalized bulk hydrogels have received a lot of attention because of their bioinspired nature. By contrast, very little is known about thin viscoelastic membranes made using similar chelator−ion pair motifs. This shortcoming is surprising because the unique interfacial properties of these membranes, namely, their self-healing and adhesion, would be ideal for capsule shells, adhesives, or for drug delivery purposes. We recently demonstrated the feasibility to fabricate 10 nm thick viscoelastic membranes from catechol-functionalized surfactants that are ionically crosslinked at the liquid/liquid interface. However, it is unclear if the vast know-how existing on the influence of the chelator−ion pair on the mechanical properties of ionically crosslinked three-dimensional (3D) hydrogels can be translated to two-dimensional (2D) systems. To address this question, we compare the dynamic mechanical properties of ionically crosslinked pyrogallol functionalized hydrogels with those of viscoelastic membranes that are crosslinked using the same chelator−ion pairs. We demonstrate that the storage and loss moduli of viscoelastic membranes follow a trend similar to that of the hydrogels, with the membrane becoming stronger as the ion−chelator affinity increases. Yet, membranes relax significantly faster than bulk equivalents. These insights enable the targeted design of viscoelastic, adhesive, self-healing membranes possessing tunable mechanical properties. Such capsules can potentially be used, for example, in cosmetics, as granular inks, or with additional work that includes replacing the fluorinated block by a hydrocarbon-based one in drug delivery and food applications.

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Section: Resultssupporting

confidence: 72%

Section: Resultsmentioning

confidence: 83%

Section: Resultsmentioning

confidence: 96%

Section: Materials and Methodsmentioning

confidence: 99%

“…When focusing on the interfacial properties, the emulsion core was composed of pure water. More details about the fitting can be found in ref .…”

Section: Materials and Methodsmentioning

confidence: 99%

See 3 more Smart Citations

Rheological Properties of Ionically Crosslinked Viscoelastic 2D Films vs. Corresponding 3D Bulk Hydrogels

Angelis

Lutz‐Bueno

Amstad

2023

ACS Appl. Mater. Interfaces

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Additive Manufacturing of Porous Biominerals

Zhao

Wittig

Angelis

et al. 2023

Adv Funct Materials

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Nature fabricates hard functional materials from soft organic scaffolds that are mineralized. To enable an energy‐efficient locomotion of these creatures while maintaining their structural stability, nature often renders parts of these minerals porous. Unfortunately, methods to produce synthetic minerals with a similar degree of control over their multi length scale porous structure remain elusive. This level of control, however, would be required to design lightweight yet robust biominerals. Here, a room temperature process is presented that combines a localized mineralization with emulsion‐based 3D printing to form cm sized biominerals possessing pores whose diameters range from the 100 s of nm up to the mm length scale. The samples encompass up to 80 wt% of CaCO3 and display a specific compressive strength that is significantly higher than that of previously reported 3D printed porous biominerals and close to those of trabecular bones. The universality of this approach by forming different types of bioactive minerals, including calcite, aragonite, and brushite is demonstrated. The ability to 3D print these materials under benign conditions renders this energy‐efficient process well‐suited to construct cm‐sized lightweight yet load‐bearing structures that might find applications, for example, in the design of the next generation of flying or motile objects.

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Charge‐Selectively Permeable Self‐Healing Microcapsules

Li,

Lutz‐Bueno,

Amstad

2023

Adv Materials Inter

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Microcapsules possessing a selective permeability are well‐suited vessels for conducting cell studies or chemical reactions that require selective exchanges of reagents over a prolonged time. Most currently reported microcapsules are single‐use delivery carriers since cargo is only released in significant amounts if their shells are damaged or the release relies on passive diffusion. Stable capsules possessing a selective, rapidly interchangeable permeability, which enables their repeated loading and unloading with selected reagents remain to be shown. Here, capsules are introduced that are composed of thin, viscoelastic, charge‐selective shells made of surfactants that are functionalized with a chelator, 3‐hydroxy‐4‐pyridinonone and crosslinked with appropriate nm‐sized ion clusters, for example composed of Fe3+/Tris or Al3+/Tris ion clusters. The charge selectivity of the shell permeability can be conveniently tuned with the crosslinking ion clusters. It is demonstrated that these capsules can be repeatedly loaded and unloaded with well‐defined substances. This feature enables their application as re‐usable selectively permeable filters to remove certain pollutants from solutions. These capsules are envisaged to be well‐suited for waste water treatment and as picoliter‐sized reaction vessels to selectively conduct chemical reactions within capsule cores while continuously supplying new reagents.

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From Surfactants to Viscoelastic Capsules

Cited by 5 publications

References 48 publications

Rheological Properties of Ionically Crosslinked Viscoelastic 2D Films vs. Corresponding 3D Bulk Hydrogels

Rheological Properties of Ionically Crosslinked Viscoelastic 2D Films vs. Corresponding 3D Bulk Hydrogels

Additive Manufacturing of Porous Biominerals

Charge‐Selectively Permeable Self‐Healing Microcapsules

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