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Aqueous foams are ubiquitous; they appear in products and processes that span the cosmetics, food, and energy industries. The versatile applicability of foams comes as a result of their intrinsic viscous and elastic properties; for example, foams are exploited as drilling fluids in enhanced oil recovery for their high viscosity. Recently, so-called capillary foams were discovered: a class of foams that have excellent stability under static conditions and whose flow properties have so far remained unexplored. The unique architecture of these foams, containing oil-coated bubbles and a gelled network of oil-bridged particles, is expected to affect foam rheology. In this work, we report the first set of rheological data on capillary foams. We study the viscoelastic properties of capillary foams by conducting oscillatory and steady shear tests. We compare our results on the rheological properties of capillary foams to those reported for other aqueous foams. We find that capillary foams, which have low gas volume fractions, exhibit long lasting rheological stability as well as a yielding behavior that is reminiscent of surfactant foams with high gas volume fractions.
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An Interpolative Slicing Algorithm for Continuously Graded Stiffness in Viscous Thread Printed Foams
Foams, essential for applications from car seats to thermal insulation, are limited by traditional manufacturing techniques that struggle to produce graded stiffness, a key feature for enhanced functionality. Here, we introduce a novel slicing algorithm for producing heterogeneous foams through viscous thread printing (VTP). Our slicer generates a single, global toolpath for the entire foam volume while modulating the viscous thread’s self-interactions along this path to program stiffness. The slicer integrates multiple meshes into a unified print space and interpolates the print speed and height based on specified mesh parameters to program the desired stiffness variations. Using both qualitative samples and quantitative compression tests, we demonstrate that our slicer can (1) generate foam stiffnesses spanning an order of magnitude, (2) achieve millimeter precision in stiffness control, and (3) continuously vary stiffness between regions of constant stiffness using arbitrary functional forms.
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- Award ID(s):
- 2212049
- PAR ID:
- 10629069
- Publisher / Repository:
- The Minerals, Metals and Materials Society
- Date Published:
- Format(s):
- Medium: X
- Location:
- https://utw10945.utweb.utexas.edu/sites/default/files/2024/M190292%20-%20addendum%20version%20%2008.pdf
- Sponsoring Org:
- National Science Foundation
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