Reconfigurable Infrared Camouflage Coatings from a Cephalopod Protein

In nature, cephalopods employ unique dynamic camouflage mechanisms. Herein, we draw inspiration from self-assembled structures found in cephalopods to fabricate tunable biomimetic camouflage coatings. The reflectance of these coatings is dynamically modulated between the visible and infrared regions of the electromagnetic spectrum in situ. Our studies represent a crucial step towards reconfigurable and disposable infrared camouflage for stealth applications

Materials and Designs for Small-Scale Propelled Devices Towards Environmental and Biological Applications

For over a decade, microscopic devices which are propelled and therefore active versus inactive nanoparticles have emerged as versatile and novel tools for a variety of applications including environmental and in vivo. In this dissertation, we aim to demonstrate the recent advances in milli and microscale devices by utilizing new designs and especially new materials towards replicating biological functions, becoming more environmentally friendly and more useful in in vivo applications.In the first section we show how selecting the appropriate set of materials and incorporating them into the structure or on the outside of milli-sized devices can give them capabilities of color-change, self-healing, and birth-like release much like the real-life counterparts from which the inspiration came from.In the second section we demonstrate the ability to utilize materials which make micromotors not only able to move in biological fluids but become completely transient and disappear without a trace while at the same time studying their time-dependent motion behavior.The third section describes the use of transient type micromotors in biological settings. We utilize these micromotors to deliver important nutrients to treat anemia, deliver a vaccine and establish an immune response and implement them in standard pill formulations for further integration into common use.We hope that these developments will help and inspire the community towards implementing these microscale devices in many common applications and possibly disrupting current technologies in the near future

Materials and Designs for Small-Scale Propelled Devices Towards Environmental and Biological Applications

For over a decade, microscopic devices which are propelled and therefore active versus inactive nanoparticles have emerged as versatile and novel tools for a variety of applications including environmental and in vivo. In this dissertation, we aim to demonstrate the recent advances in milli and microscale devices by utilizing new designs and especially new materials towards replicating biological functions, becoming more environmentally friendly and more useful in in vivo applications.In the first section we show how selecting the appropriate set of materials and incorporating them into the structure or on the outside of milli-sized devices can give them capabilities of color-change, self-healing, and birth-like release much like the real-life counterparts from which the inspiration came from.In the second section we demonstrate the ability to utilize materials which make micromotors not only able to move in biological fluids but become completely transient and disappear without a trace while at the same time studying their time-dependent motion behavior.The third section describes the use of transient type micromotors in biological settings. We utilize these micromotors to deliver important nutrients to treat anemia, deliver a vaccine and establish an immune response and implement them in standard pill formulations for further integration into common use.We hope that these developments will help and inspire the community towards implementing these microscale devices in many common applications and possibly disrupting current technologies in the near future

Multigear Bubble Propulsion of Transient Micromotors

Transient, chemically powered micromotors are promising biocompatible engines for microrobots. We propose a framework to investigate in detail the dynamics and the underlying mechanisms of bubble propulsion for transient chemically powered micromotors. Our observations on the variations of the micromotor active material and geometry over its lifetime, from initial activation to the final inactive state, indicate different bubble growth and ejection mechanisms that occur stochastically, resulting in time-varying micromotor velocity. We identify three processes of bubble growth and ejection, and in analogy with macroscopic multigear machines, we call each process a gear. Gear 1 refers to bubbles that grow on the micromotor surface before detachment while in Gear 2 bubbles hop out of the micromotor. Gear 3 is similar in nature to Gear 2, but the bubbles are too small to contribute to micromotor motion. We study the characteristics of these gears in terms of bubble size and ejection time, and how they contribute to micromotor displacement. The ability to tailor the shell polarity and hence the bubble growth and ejection and the surrounding fluid flow is demonstrated. Such understanding of the complex multigear bubble propulsion of transient chemical micromotors should guide their future design principles and serve for fine tuning the performance of these micromotors

Cephalopod-inspired tunable infrared camouflage

Cephalopods are known as the chameleons of the sea - they can alter their skin's coloration, pattern, texture, and reflectivity to blend into the surrounding environment. Despite much research effort, there are few known strategies (natural or artificial) for emulating the unique dynamic reflectivity and coloration of cephalopods. We have drawn inspiration from self-assembled structures found in cephalopods to fabricate tunable biomimetic camouflage coatings. The reflectance of these coatings can be dynamically modulated between the visible and IR regions of the electromagnetic spectrum in situ. Our studies represent a crucial step towards reconfigurable and disposable IR camouflage for stealth applications

Transient Micromotors That Disappear When No Longer Needed.

Transient self-destroyed micromotors that autonomously disappear in biological media at controlled rates upon completing their task, without leaving a toxic residue, are presented. The propulsion and degradation characteristics of the self-destroyed Mg/ZnO, Mg/Si, and Zn/Fe Janus micromotors and single-component Zn micromotors are described. The degradation of the Janus micromotors relies on the different corrosion rates of their core-shell components. Inductively coupled plasma optical emission spectrometry measurements are used to probe the time-dependent degradation of the different constituents of the micromotors. The toxicity of the transient micromotors is discussed toward their potential use in biomedical applications. This concept of transient micromotors offers considerable potential for diverse practical applications in the near future

Multistimuli-Responsive Camouflage Swimmers

Multistimuli-responsive camouflaging and autonomously propelled swimmers are presented. These bioinspired artificial swimmers are capable of color changing in response to a variety of environmental stimuli such as temperature, pH, and light. By multiplexing different stimuli-responsive materials on a single swimmer, a vast library of independently addressable colors can be achieved. Unlike other color-changing robots, our color-changing swimmers can move autonomously in solution and are decoupled from tethered supports. The utilized leuco dyes, pH indicators, and phosphorescent powders display excellent reversibility and prolonged color retention. Finally, we design camouflage patterns which render the swimmers invisible against virtually any background, while revealing the swimmer upon changing the environmental conditions. By mimicking animal camouflage strategies these artificial swimmers present a significant step toward realizing multienvironmental stimuli-responsive color-changing strategies for the next generation of smart robotics. Such capabilities can be further enhanced by coupling color-changing ability with stimuli-triggered speed or shape change

Multistimuli-Responsive Camouflage Swimmers

Multistimuli-responsive camouflaging and autonomously propelled swimmers are presented. These bioinspired artificial swimmers are capable of color changing in response to a variety of environmental stimuli such as temperature, pH, and light. By multiplexing different stimuli-responsive materials on a single swimmer, a vast library of independently addressable colors can be achieved. Unlike other color-changing robots, our color-changing swimmers can move autonomously in solution and are decoupled from tethered supports. The utilized leuco dyes, pH indicators, and phosphorescent powders display excellent reversibility and prolonged color retention. Finally, we design camouflage patterns which render the swimmers invisible against virtually any background, while revealing the swimmer upon changing the environmental conditions. By mimicking animal camouflage strategies these artificial swimmers present a significant step toward realizing multienvironmental stimuli-responsive color-changing strategies for the next generation of smart robotics. Such capabilities can be further enhanced by coupling color-changing ability with stimuli-triggered speed or shape change

Multistimuli-Responsive Camouflage Swimmers

Multistimuli-responsive camouflaging and autonomously propelled swimmers are presented. These bioinspired artificial swimmers are capable of color changing in response to a variety of environmental stimuli such as temperature, pH, and light. By multiplexing different stimuli-responsive materials on a single swimmer, a vast library of independently addressable colors can be achieved. Unlike other color-changing robots, our color-changing swimmers can move autonomously in solution and are decoupled from tethered supports. The utilized leuco dyes, pH indicators, and phosphorescent powders display excellent reversibility and prolonged color retention. Finally, we design camouflage patterns which render the swimmers invisible against virtually any background, while revealing the swimmer upon changing the environmental conditions. By mimicking animal camouflage strategies these artificial swimmers present a significant step toward realizing multienvironmental stimuli-responsive color-changing strategies for the next generation of smart robotics. Such capabilities can be further enhanced by coupling color-changing ability with stimuli-triggered speed or shape change