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Stick-slip Motion of Silver Chloride Colloids in Dilute Hydrogen Peroxide


“Emergent, Collective Oscillations of Self-Mobile Particles and Patterned Surfaces under Redox Conditions”
Michael Ibele, Paul E. Lammert, Vincent H. Crespi, and Ayusman Sen
ACS Nano 2010, 4, 4845-4851,     DOI: 10.1021/nn101289p

Supplemental Video:
UV-illuminated silver chloride (AgCl) particles undergoing "stick-slip" motion in solution over a microscope slide. The solution contains 0.33% H2O2 in water. The video is 194 μm in width. Movie plays in real-time.

Motion of Silver Chloride Colloids in Dilute Hydrogen Peroxide with Silica Tracers


“Emergent, Collective Oscillations of Self-Mobile Particles and Patterned Surfaces under Redox Conditions”
Michael Ibele, Paul E. Lammert, Vincent H. Crespi, and Ayusman Sen
ACS Nano 2010, 4, 4845-4851,     DOI: 10.1021/nn101289p

Supplemental Video:
A solution containing AgCl particles (darker objects), silica tracer spheres (lighter objects), and 1% H2O2 in water. The particles are illumined with UV light over a microscope slide. The AgCl particles are seen to move through solution, and alternately bind and release the silica tracer particles. The video is 98 μm in width. Movie plays in real-time.

Motion of Silver Colloids in Dilute Hydrogen Peroxide with Silica Tracers

Motion of Silver Colloids in Dilute Hydrogen Peroxide with Silica Tracers

“Emergent, Collective Oscillations of Self-Mobile Particles and Patterned Surfaces under Redox Conditions”
Michael Ibele, Paul E. Lammert, Vincent H. Crespi, and Ayusman Sen
ACS Nano 2010, 4, 4845-4851,     DOI: 10.1021/nn101289p

Supplemental Video:
A solution containing single crystal silver particles (darker objects), silica tracer spheres (lighter objects), 0.25 mM KCl, and 0.63% H2O2 in water. The particles are illuminated with UV light over a microscope slide. The silver particles are seen to move through solution, and alternately bind and release the silica tracer particles (qualitatively similar to the above video involving AgCl particles). The video is 98 μm in width. Movie plays in real-time.



“Emergent, Collective Oscillations of Self-Mobile Particles and Patterned Surfaces under Redox"
Motion of Dense Collections of Silver Chloride Colloids in Dilute Hydrogen Peroxide
"Conditions"
Michael Ibele, Paul E. Lammert, Vincent H. Crespi, and Ayusman Sen
ACS Nano 2010, 4, 4845-4851,     DOI: 10.1021/nn101289p

Supplemental Video:
A solution containing AgCl particles and 1% H2O2 in water under UV illumination. The AgCl particles alternately attract then repel one another. Traveling waves of particle motion can be seen traversing the illuminated area. Synchronization of particle attractions/repulsions is also observed over a variety of length scales. The video is 194 μm in width. Movie plays in real-time.

Prior to this movie being recorded and prior to the particles' exposure to H2O2, the particles were placed in pure deionized water and illuminated with UV light for 25 min. H2O2 was then added to the system to reach a final concentration of 1%. This movie was recorded approximately 5 minutes after the addition of H2O2.

Wave of Motion Across Silver Chloride and Silica Colloids


“Emergent, Collective Oscillations of Self-Mobile Particles and Patterned Surfaces under Redox Conditions”
Michael Ibele, Paul E. Lammert, Vincent H. Crespi, and Ayusman Sen
ACS Nano 2010, 4, 4845-4851,     DOI: 10.1021/nn101289p

Supplemental Video:
A UV-illuminated aqueous solution containing 2.3 μm silica tracer particles (lighter objects), silver chloride colloids (darker objects), and 1% (v/V) H2O2. A reaction wave moves in from the upper left and is joined by a second wave from the upper right. After the front passes, the tracer particles are clumped. The field of view is 485 μm wide. Movie plays in real time.


Silver Disc Oscillating in KCl and H2O2

“Emergent, Collective Oscillations of Self-Mobile Particles and Patterned Surfaces under Redox Conditions”
Michael Ibele, Paul E. Lammert, Vincent H. Crespi, and Ayusman Sen
ACS Nano 2010, 4, 4845-4851,     DOI: 10.1021/nn101289p

Supplemental Video:
A UV-illuminated aqueous solution containing 2.3 μm silica tracer particles, 0.33 mM KCl, and 0.17% H2O2 is imaged above a 25 μm diameter silver disk that has been patterned onto a SiO2 surface. The silica tracer particles are alternately attracted to and repelled from the silver surface. The silver disk is discolored by deposits of AgCl which have formed in situ. One such deposit resembles a long line that traverses the entire disk. Such spatially defined deposits are common in this system. Movie plays in real-time.



“Emergent, Collective Oscillations of Self-Mobile Particles and Patterned Surfaces under Redox Conditions”
Silver Features in HCl and H2O2 Oscillating in Color
Michael Ibele, Paul E. Lammert, Vincent H. Crespi, and Ayusman Sen
ACS Nano 2010, 4, 4845-4851,     DOI: 10.1021/nn101289p

Supplemental Video:
A UV-illuminated aqueous solution containing 2.3 μm silica tracer particles, 0.33 mM HCl, and 0.17% H2O2 is imaged above an array of 9 μm diameter silver disks with 11 μm spacings. As a traveling wave of tracer particle motion passes the array, the disks appear to flash on and off as their color alternates between reflective silver and darkened AgCl.

The movie has two distinct segments. The first segment is a real-time recording of the phenomenon taken at 30 frames per second. The second segment shows the movie slowed down to 1/10th speed (3 fps). Because of the relatively slow frame rate of the camera used verses the speed at which this remarkably fast phenomenon occurs, it is possible that some of the color variations of the surface features were not captured on film because they occurred between the frames.



“Emergent, Collective Oscillations of Self-Mobile Particles and Patterned Surfaces under Redox Conditions”
Silver Disc Oscillating in KCl and H2O2 and the Measured Electrical Current
Michael Ibele, Paul E. Lammert, Vincent H. Crespi, and Ayusman Sen
ACS Nano 2010, 4, 4845-4851,     DOI: 10.1021/nn101289p

Supplemental Video:
A UV-illuminated aqueous solution containing 2.3 μm silica tracer particles, 0.17 mM HCl, and 0.17% H2O2 is imaged above a 90 μm diameter silver disk that has been patterned onto a SiO2 surface. Connected to the silver disk is a silver wire that leads out along the surface to a silver contact pad located outside the liquid. The silver wire is coated with an insulating Su-8 polymer to isolate it from solution. Movie plays in real time.

The silver disk is discolored by deposits of AgCl which have formed in situ. The silica tracer particles are alternately attracted to and repelled from the silver surface. As this motion occurs, the current is measured between the silver disk working electrode and a gold wire counter electrode placed in the above solution. This current is plotted below the video. Negative currents are oxidative with respect to the silver disk. Attractive motions of the tracer particles accompany oxidative current spikes.

Schooling Behavior of UV-Illuminated Silver Chloride Colloids


“Schooling Behavior of Light-Powered Autonomous Micromotors in Water”
Michael Ibele, Thomas E. Mallouk, and Ayusman Sen
Angew. Chem. 2009, 48 (18), 3308-3312, DOI: 10.1002/anie.200804704

Supplemental Video:
Schooling behavior of UV-illuminated silver chloride colloids. Silver chloride particles approximately 2 μm in size are filmed in deionized water. At 2 seconds into the film they are exposed to UV light and begin to move. At longer times large schools of particles develop. Viewing window is 195 μm across. Videos play in real time.

Assembly of Silver Chloride and Amidine Spheres to form Janus Motors


“Schooling Behavior of Light-Powered Autonomous Micromotors in Water”
Michael Ibele, Thomas E. Mallouk, and Ayusman Sen
Angew. Chem. 2009, 48 (18), 3308-3312, DOI: 10.1002/anie.200804704

Supplementary Video:
Assembly of UV-illuminated silver chloride and amidine spheres to form Janus motors. Silver chloride colloids (darker objects) are mixed with amidine coated polystyrene spheres (translucent objects) in deionized water and are illuminated with UV light. The ions produced by the silver chloride decomposition attract in the amidine spheres, where they electrostatically attach to the silver chloride. The addition of the inert amidine sphere makes the silver chloride significantly more asymmetric, and thus the previously random motion of the silver chloride becomes more directed. Viewing window is 195 μm across. Videos play in real time.

Predator-Prey Behavior of Silica Spheres Towards UV-Illuminated Silver Chloride


“Schooling Behavior of Light-Powered Autonomous Micromotors in Water”
Michael Ibele, Thomas E. Mallouk, and Ayusman Sen
Angew. Chem. 2009, 48 (18), 3308-3312, DOI: 10.1002/anie.200804704

Supplementary Video:
“Predator-prey” behavior of silica spheres towards UV-illuminated silver chloride. Silver chloride colloids (darker objects) are mixed with 2 μm silica spheres (translucent objects) in deionized water. UV-Illumination commences three seconds into the film, and the silver chloride begins to move The inert silica spheres are then seen to seek out and surround the mobile silver chloride particles in much the same way a neutrophil seeks out bacteria.



Reversible Schooling by Silver Chloride Colloids Previously Exposed to UV-Light
“Schooling Behavior of Light-Powered Autonomous Micromotors in Water”
Michael Ibele, Thomas E. Mallouk, and Ayusman Sen
Angew. Chem. 2009, 48 (18), 3308-3312, DOI: 10.1002/anie.200804704

Supplementary Video:
Reversible schooling by silver chloride colloids previously exposed to UV-light. Silver chloride colloids in deionized water which have been previously exposed to UV light undergo a strange phenomenon when the UV light is removed (leaving only visible wavelength illumination). Previously collected schools will condense further to form tighter schools. If the UV light is turned back on, the schools will expand back to their original sizes. This phenomenon is not completely understood and does not occur for fresh silver chloride colliods which have never been exposed to UV light. As the movie begins the UV light is off. It is turned on again at 5 seconds, 24 seconds, and 47 seconds, and off at 13 seconds, 30 seconds, and 52 seconds. Viewing window is 195 μm across. Videos play in real time.

Chemotaxis of Non-Biological Nanorods


“Chemotaxis of Non-Biological Nanorods”
Yiying Hong, Nicole M. K. Blackman, Nathaniel D. Kopp, Ayusman Sen, and Darrell Velegol
Phys. Rev. Lett. 2007, 99, 178103. DOI: 10.1103/PhysRevLett.99.178103

Supplementary Video:
Chemotaxis of PtAu rods. PtAu rods move toward the 30% H2O2 soaked hydrogel (top left corner) at 0.7 hour of experiment. Movie was taken by transmission microscope at bright field at 50 times magnification and 30 times the real speed.

Real-time remote steering of striped metallic rods in a 5% hydrogen peroxide solution.


“Catalytic Nanomotors: Remote-Controlled Autonomous Movement of Striped Metallic Nanorods”
Timothy R. Kline, Walter F. Paxton, Thomas E. Mallouk, and Ayusman Sen
Angew. Chem., Int. Ed. 2005, 44, 744, DOI: 10.1002/anie.200461890

Referee Video:
Real-time remote steering of striped metallic rods in a 5% hydrogen peroxide solution.
Real-time remote-controlled 2 μm magnetic metallic nanorods in a 2.5% hydrogen peroxide solution that are steered by magnetic field which is turned off toward the end of the movie.


“Catalytic Nanomotors: Remote-Controlled Autonomous Movement of Striped Metallic Nanorods”
Timothy R. Kline, Walter F. Paxton, Thomas E. Mallouk, and Ayusman Sen
Angew. Chem., Int. Ed. 2005, 44, 744, DOI: 10.1002/anie.200461890

Video:
Real-time remote-controlled 2 μm magnetic metallic nanorods in a 2.5% hydrogen peroxide solution that are steered by magnetic field which is turned off toward the end of the movie.

Real-time rotational movement of a 100 μm diameter free gear with Pt catalysts on the gear teeth in a 1% hydrogen peroxide solution.


“Directed Rotational Motion of Microscale Objects Using Interfacial Tension Gradients”
Jeffrey Catchmark, Shyamala Subramanian, and Ayusman Sen
Small 2005, 1, 202, DOI: 10.1002/smll.200400061

Video:
Real-time rotational movement of a 100 μm diameter free gear with platinum catalysts on the gear teeth in a 1% hydrogen peroxide solution.

Real-time Brownian movement of 2 μm platinum/gold rods in pure water.


“Catalytic Nanomotors: Autonomous Movement of Striped Nanorods”
Walter F. Paxton, Kevin C. Kistler, Christine C. Olmeda, Ayusman Sen, Sarah K. St. Angelo, Yanyan Cao, Thomas E. Mallouk, Pau; E. Lammert, and Vincent H. Crespi
J. Am. Chem. Soc. 2004, 126, 13424, 10.1021/ja047697z

Video 1:
Real-time Brownian movement of 2 μm platinum/gold rods in pure water.

Real-time non-Brownian movement of 2 μm platinum/gold rods in a 2.5% hydrogen peroxide solution.


“Catalytic Nanomotors: Autonomous Movement of Striped Nanorods”
Walter F. Paxton, Kevin C. Kistler, Christine C. Olmeda, Ayusman Sen, Sarah K. St. Angelo, Yanyan Cao, Thomas E. Mallouk, Pau; E. Lammert, and Vincent H. Crespi
J. Am. Chem. Soc. 2004, 126, 13424, 10.1021/ja047697z

Video 2:
Real-time non-Brownian movement of 2 μm platinum/gold rods in a 2.5% hydrogen peroxide solution.