Abstract Detail

Recent Topics Posters

Wade, Jayla [1], Quest, Madyson [2], Lazarus, Nathan [2], Burke, Janelle [3], Hanrahan, Brendan [4].

BIOMIMETIC 4D PRINTED ERODIUM CICUTARIUMTHERMO-RESPONSIVE ACTUATOR.

Biomimicry is an accelerating area of research, especially within the field of soft robotics, yet the application of plant-inspired models is still lacking. One particularly enticing challenge is a self-digging robot, and for that we find inspiration in the Erodium cicutarium L. Erodium plants disperse their progeny utilizing a self-burial mechanism relying on changes in external parameters such as humidity, light, and temperature.  Using a technique known as “4D printing”, where a 3D-printed object has a stimuli-induced shape change, we mimic the drilling motion of the Erodium seed. Thermo-responsive thermoplastics polyactic acid (PLA) and polyethylene terephthalate gylcol (PETG) were selected for their shape memory response realized at different temperatures. These actuators were designed to sequentially unfurl from a helical starting shape like the Erodium seed. We varied the helical pitch of the awn and the starting orientation of the seed in order to assess the digging characteristics of each actuator. For the experiments, the actuators were placed on an artificial sand bed in an oven and the temperature was increased from  45 C to 80 C in 30 minutes while video was recorded. The deformed (helical) and as-printed parent phase (unfurled) of the actuators were measured as well as the depth of the artificial seed-head. The actuators with a lower helical pitch (tighter coil) had a larger or quicker rate of burial depth than the actuators with higher pitch. Time-lapse footage revealed the importance of the initial orientation. Burial efficiency was directly influenced by seed anchorage as actuators with initially angled seed orientations submerged seed head for longer durations than seeds oriented horizontally to the sand bed. An addition of an extra 90 mm tail on the artificial seed enabled this anchoring mechanism and promoted drilling-like motion of the seed head. The maximum depth obtained was approximately 5mm, although often a buried seed would un-bury at the end of the shape memory movement due to seed head design and the low density of the artificial sand.  This movement of seeds across soil is a reliable mechanism in distancing progeny away from the parent plant in order to reach suitable germination sites and increase fitness. This is the first demonstration of digging from an Erodium-inspired soft robotic actuator and with further optimization, this actuator could be used as a sensor platform for soil health monitoring or seismic sensing. 
Keywords: Biomimicry, 4D Printing, Erodium cicutarium

1 - 6515 Belcrest Rd, 404-C, Hyattsville, MD, 20782, USA
2 - Adelphi Laboratory Center, 2800 Powder Mill Rd, Hyattsville, MD, 20783, USA
3 - Howard University, Dept. Of Biology, 415 College St. NW, Just Hall 328, Washington, DC, 20059, United States
4 - Adelphi Laboratory Centre, 2800 Powder Mill RD, Hyattsville, MD, 20783, ISA

Keywords:
Biomimicry
^{4D Printing}
Erodium cicutarium
Shape memory polymers.

Presentation Type: Recent Topics Poster
Session: P1, Recent Topics Posters
Location: Virtual/Virtual
Date: Thursday, July 22nd, 2021
Time: 5:00 PM(EDT)
Number: P1RT031
Abstract ID:1422
Candidate for Awards:None