Browsing by Author "Grzybowski, B. A."

Now showing 1 - 3 of 3

Open Access
Artificial heliotropism and nyctinasty based on optomechanical feedback and no electronics
(Mary Ann Liebert, 2018) Baytekin, B.; Cezan, S. D.; Baytekin, H. T.; Grzybowski, B. A.
Although plants are typically not considered an inspiration for designing motile robots, they do perform a variety of intricate motion patterns, including diurnal cycles of sun tracking (heliotropism) and leaf opening (nyctinasty). In real plants, these motions are controlled by complex, feedback-based biological mechanisms that, to date, have been mimicked only in computer-controlled artificial systems. This work demonstrates both heliotropism and nyctinasty in a system in which few simple, but strategically positioned thermo-responsive springs and lenses form a feedback loop controlling these motions and substantiating a behavioral analogy to "plants." In particular, this feedback allows the "artificial plant" to reach and stabilize at a metastable position in which the solar flux on the "plants" and the solar power "leaves" are maximized. Unlike many soft robotic systems, our "plants" are completely autonomous, in that, they do not require any external controls or power sources. Bioinspired designs such as this could be of interest for soft robotic systems in which materials alone - rather than power-consuming electronic circuitry - control the motions.
Open Access
Mechanochemical activation and patterning of an adhesive surface toward nanoparticle deposition
(American Chemical Society, 2015) Baytekin, H. T.; Baytekin, B.; Huda, S.; Yavuz, Z.; Grzybowski, B. A.
Mechanical pulling of adhesive tape creates radicals on the tapes surface. These radicals are capable of reducing metal salts to the corresponding metal nanoparticles. In this way, the mechanically activated tape can be decorated with various types of nanoparticles, including Au, Ag, Pd, or Cu. While retaining their mechanical properties and remaining "sticky, " the tapes can exhibit new properties derived from the presence of metal nanoparticles (e.g., bacteriostaticity, increased electrical conductivity). They can also be patterned with nanoparticles only at selective locations of mechanical activation.
Open Access
Slit tubes for semisoft pneumatic actuators
(Wiley, 2018) Belding, L.; Baytekin, Bilge; Baytekin, Hasan Tarık; Rothemund, P.; Verma, M. S.; Nemiroski, A.; Sameoto, D.; Grzybowski, B. A.; Whitesides, G. M.
This article describes a new principle for designing soft or ‘semisoft’ pneumatic actuators: SLiT (for SLit-in-Tube) actuators. Inflating an elastomeric balloon, when enclosed by an external shell (a material with higher Young's modulus) containing slits of different directions and lengths, produces a variety of motions, including bending, twisting, contraction, and elongation. The requisite pressure for actuation depends on the length of the slits, and this dependence allows sequential actuation by controlling the applied pressure. Different actuators can also be controlled using external “sliders” that act as reprogrammable “on-off” switches. A pneumatic arm and a walker constructed from SLiT actuators demonstrate their ease of fabrication and the range of motions they can achieve.