Influence of fluid viscosity on elastocapillary coiling
ORAL
Abstract
A typical spider web is composed of many different types of silk, each designed for a specific
purpose. The capture thread is a soft, extensible silk thread decorated with sticky glue droplets
which adhere prey to the web. Elastocapillary interactions cause the silk thread to buckle and then
coil within the glue droplets as the thread is compressed. The surface tension of the droplets keep
the fiber taut. This means that the capture thread can be compressed far beyond the length at which
an uncoated fiber would begin to sag while remaining taut. It is hypothesized that this morphology
evolved to prevent the web from tangling with itself during wind loading or insect impact. We
expand upon previous studies by exploring the effects of droplet viscosity on the dynamic response
of the drop on fiber system. We test a model system composed of a polymer fiber and silicone oil
droplets and measure the sub micronewton tension in the thread during coiling using micropipette
force sensing.The results of this study will provide a deeper understanding of how spider webs
work and could be used to create solid-liquid hybrid metamaterials.
purpose. The capture thread is a soft, extensible silk thread decorated with sticky glue droplets
which adhere prey to the web. Elastocapillary interactions cause the silk thread to buckle and then
coil within the glue droplets as the thread is compressed. The surface tension of the droplets keep
the fiber taut. This means that the capture thread can be compressed far beyond the length at which
an uncoated fiber would begin to sag while remaining taut. It is hypothesized that this morphology
evolved to prevent the web from tangling with itself during wind loading or insect impact. We
expand upon previous studies by exploring the effects of droplet viscosity on the dynamic response
of the drop on fiber system. We test a model system composed of a polymer fiber and silicone oil
droplets and measure the sub micronewton tension in the thread during coiling using micropipette
force sensing.The results of this study will provide a deeper understanding of how spider webs
work and could be used to create solid-liquid hybrid metamaterials.
*This research was supported by the MRSEC Program of the National Science Foundation under Award No. DMR-1720256.
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Presenters
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JP P Raimondi
- University of California, Santa Barbara