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Abstract The dissolution of a polymeric solid typically starts with the absorption of solvent molecules, followed by swelling and volume expansion. Only when the extent of swelling reaches a threshold can the polymer chains be disentangled and then dissolved into the solvent. When the polymeric solid is encapsulated in a rigid shell, the swelling process will be impeded. Despite the widespread use of this process, it is rarely discussed in the literature how the polymeric solid is dissolved from the core for the generation of colloidal hollow particles. Recent studies have started to shed light on the mechanistic details involved in the formation of hollow particles through a template‐directed process. Depending on the nature of the material used for the template, the removal of the template may involve different mechanisms and pathways, leading to the formation of distinct products. Here, a number of examples are used to illustrate this important phenomenon that is largely neglected in the literature. This article also discusses how the swelling of a polymeric template encapsulated in a rigid shell can be leveraged to fabricate new types of functional colloidal particles.
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Modeling and measuring the absorption-induced expansion of swellable organically modified silica
We present a theoretical framework that describes the force generated by the expansion of swellable organically modified silica (SOMS) upon exposure to organic solvent. The total swelling force, produced from the differential contributions of localized swelling domains, is related logarithmically to the amount of material confined to a rigid space. The model is further parameterized according to the physical dimensions of that space and the intrinsic swellability of SOMS. This mathematical representation is validated experimentally using a piston force sensor apparatus, which shows that the solvent-induced force and pressure exerted by SOMS increase logarithmically with the amount of material that is present. Comparison with theory implies that the commercially available varieties of SOMS CyclaSorbTM and OsorbTM have Young’s expansion moduli YC ∼ 0.8 MPa and YO ∼ 0.7 MPa, respectively, which succinctly quantifies their relative behavior. The theoretical model and experimental technique should be widely applicable to other swellable and stimuli-responsive materials.
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- Award ID(s):
- 1852095
- PAR ID:
- 10596897
- Publisher / Repository:
- American Institute of Physics
- Date Published:
- Journal Name:
- AIP Advances
- Volume:
- 10
- Issue:
- 6
- ISSN:
- 2158-3226
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
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