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NanoDay@Penn

NanoDay@Penn 20142014 Image Contest Entries

 

Liquid Crystal image  

2014 Best Artistic Image Winner

Liquid Crystal
Iris Liu

A thin layer of smectic liquid crystal is spread out on a glass substrate. Liquid crystal molecules in contact with air prefer a perpendicular alignment, while in contact with the substrate, molecules prefer a planar alignment. To satisfy such alignment, smectic liquid crystal molecules can form two types of defect: focal conic domains and oily streaks. Smectics manifest extreme sensitivity to boundary conditions, in a small region both patterns emerge, interlacing each other, resembling ancient woven textiles. This image shows such a region under cross-polarizer, where focal conical domains emerge as four brushes, while oily streaks look like close-packed tiles.

Authors: Iris B. Liu, Yimin Luo, Francesca Serra, Mohamed A. Gharbi, Nathan D. Bade, Randall D. Kamien, Shu Yang, Kathleen J. Stebe

     
Transmission electron microscope of a deformed carbon nanotube being torn apart under mechanical stress.  

2014 Best Scientific Image Winner

Deformed carbon nanotube being torn apart under mechanical stress.
John Qi

Transmission electron microscope of a deformed carbon nanotube being torn apart under mechanical stress. The carbon nanotube is connected to bulk amorphous carbon structures.

     
 

2014 Best Animation Winner

Cell Injection
Martha Grady

Human dermal fibroblast cells injected with food coloring. Instrument is Eppendorf Injectman 4 and Femtojet 4i. Cells are on the order of 100 um in size. A fluid volume less than a nanoliter is delivered to each cell. Volumes as small as femtoliters can be delivered using this set up. Video is actual recordings.

https://www.youtube.com/watch?v=bG2l2M2eUrY

     
Plenty of Room at the Bottom  

Meiyang Cui

     
Transmission electron micrograph of a highly crystalline multilayered graphene nanoribbon under electrical bias.  

John Qi

Transmission electron micrograph of a highly crystalline multilayered graphene nanoribbon under electrical bias.

     
Transmission electron micrograph of a highly crystalline multilayered graphene nanoribbon under electrical bias.  

John Qi

Scanning electron micrograph of graphene after oxygen plasma etch. A layer of sub-micron polymer beads were used as an etch mask. White contrast represents the SiO2 substrate. Grey contrast represents the graphene.

     
Transmission electron micrograph of a highly crystalline multilayered graphene nanoribbon under electrical bias.  

John Qi

Scanning electron micrograph of graphene suspended over an array of 1 x 1 um square holes. Micrograph taken at a 52 degree tilt angle. The suspended graphene appears grey, tears in graphene appear black (vacuum), gold electrodes are also present in the image (bottom and right).

     
Polarized Light – Aptes  

Polarized Light – Aptes
Yimin Luo

Micropillars (diameter = 100 microns) are patterned on a substrate through soft lithography. The substrate is further functionalized with a silane. A thin layer of smectic liquid crystal is deposited on the surface and pinned at the edges of the pillars. Smectic liquid crystals self-organize into hierarchical, highly regular defect structures called focal conic domains (FCDs), resembling flower petals radiating from the edge of the pillars. The arrangements and the sizes of the FCDs depend on the local curvature and the anchoring strength. This image shows such a flower under cross-polarizer, where the layering of smectics within each FCDs are clearly visible.

Authors: Yimin Luo, Iris B. Liu, Mohamed A. Gharbi, Francesca Serra, Nathan D. Bade, Shu Yang, Randall D. Kamien, Kathleen J. Stebe

     
Smectic liquid crystals  

Smectic liquid crystals
Francesca Serra

Smectic liquid crystals are birefringent materials where molecules arrange into fluid parallel layers. Under certain conditions, they form topological defects called focal conic domains. The arrangement of the smectic layers in focal conic domains bends the incident light so that these defects act as microlenses, whose focal lengths depend on the size of the focal conic domain. Here, many focal conic domains are self-assembled into a flower-like pattern around a 100-micron wide epoxy micropost, with the smectic liquid crystals pinned at the edges of the post. In the picture, viewed in bright field microscopy, a letter P (like Penn) is projected by all the microlenses that lay approximately at the same height.

Authors: Francesca Serra, Yimin Luo, Iris B. Liu, Nathan D. Bade, Mohamed A. Gharbi, Randall D. Kamien, Shu Yang, Kathleen J. Stebe

     
Vertical Graphene  

Vertical Graphene
Keivan Davami

Vertical graphene (VG) sheets were synthesized using a radio-frequency (RF) PECVD method on a silicon substrate. While these sheets are not completely vertical, since most of them do not lie on the substrate surface, they are still colloquially called VG.

 

 

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