scholarly journals Chirality in curved polyaromatic systems

2017 ◽  
Vol 46 (6) ◽  
pp. 1643-1660 ◽  
Author(s):  
Michel Rickhaus ◽  
Marcel Mayor ◽  
Michal Juríček
Keyword(s):  
Gaussian Curvature ◽  
Carbon Allotrope ◽  
Carbon Allotropes ◽  
Negative Gaussian Curvature ◽  
Helical Chirality

Chiral non-planar polyaromatic systems that display zero, positive or negative Gaussian curvature are analysed and their potential to ‘encode’ chirality of larger sp2-carbon allotropes is evaluated. Shown is a hypothetical peanut-shaped carbon allotrope, where helical chirality results from the interplay of various curvature types.

Negative Gaussian curvature induces significant suppression of thermal conduction in carbon crystals

Nanoscale ◽  
2017 ◽  
Vol 9 (37) ◽  
pp. 14208-14214 ◽  
Author(s):  
Zhongwei Zhang ◽  
Jie Chen ◽  
Baowen Li
Keyword(s):  
Gaussian Curvature ◽  
Thermal Conduction ◽  
Negative Curvature ◽  
Positive Curvature ◽  
Significant Suppression ◽  
Carbon Allotropes ◽  
Zero Curvature ◽  
Negative Gaussian Curvature

From the mathematic category of surface Gaussian curvature, carbon allotropes can be classified into three types: zero curvature, positive curvature, and negative curvature.

2D carbon sheets with negative Gaussian curvature assembled from pentagonal carbon nanoflakes

2018 ◽  
Vol 20 (14) ◽  
pp. 9123-9129 ◽  
Author(s):  
Cunzhi Zhang ◽  
Fancy Qian Wang ◽  
Jiabing Yu ◽  
Sheng Gong ◽  
Xiaoyin Li ◽  
...  
Keyword(s):  
Gaussian Curvature ◽  
The Novel ◽  
Carbon Allotropes ◽  
Graphene Nanoflakes ◽  
Negative Gaussian Curvature ◽  
Carbon Nanoflakes

Based on the recent experimental synthesis of pentagonal graphene nanoflakes and the novel properties of penta-graphene, we report a series of 2D assembled carbon allotropes (CG568-80, CG568-180 and CG568-320) that have unusual properties.

scholarly journals Carbon Allotrope-Based Optical Fibers for Environmental and Biological Sensing: A Review

Sensors ◽  
2020 ◽  
Vol 20 (7) ◽  
pp. 2046 ◽  
Author(s):  
Stephanie Hui Kit Yap ◽  
Kok Ken Chan ◽  
Swee Chuan Tjin ◽  
Ken-Tye Yong
Keyword(s):  
Optical Fiber ◽  
Optical Fibers ◽  
High Sensitivity ◽  
Optical Fiber Sensors ◽  
Functional Coating ◽  
Fiber Sensors ◽  
Carbon Allotrope ◽  
Carbon Allotropes ◽  
Sensing Technology ◽  
Wide Range

Recently, carbon allotropes have received tremendous research interest and paved a new avenue for optical fiber sensing technology. Carbon allotropes exhibit unique sensing properties such as large surface to volume ratios, biocompatibility, and they can serve as molecule enrichers. Meanwhile, optical fibers possess a high degree of surface modification versatility that enables the incorporation of carbon allotropes as the functional coating for a wide range of detection tasks. Moreover, the combination of carbon allotropes and optical fibers also yields high sensitivity and specificity to monitor target molecules in the vicinity of the nanocoating surface. In this review, the development of carbon allotropes-based optical fiber sensors is studied. The first section provides an overview of four different types of carbon allotropes, including carbon nanotubes, carbon dots, graphene, and nanodiamonds. The second section discusses the synthesis approaches used to prepare these carbon allotropes, followed by some deposition techniques to functionalize the surface of the optical fiber, and the associated sensing mechanisms. Numerous applications that have benefitted from carbon allotrope-based optical fiber sensors such as temperature, strain, volatile organic compounds and biosensing applications are reviewed and summarized. Finally, a concluding section highlighting the technological deficiencies, challenges, and suggestions to overcome them is presented.

scholarly journals Encoding Gaussian curvature in glassy and elastomeric liquid crystal solids

2016 ◽  
Vol 472 (2189) ◽  
pp. 20160112 ◽  
Author(s):  
Cyrus Mostajeran ◽  
Mark Warner ◽  
Taylor H. Ware ◽  
Timothy J. White
Keyword(s):  
Gaussian Curvature ◽  
Logarithmic Spiral ◽  
Geometric Constraints ◽  
Intrinsic Geometry ◽  
Constant Gaussian Curvature ◽  
Spatially Inhomogeneous ◽  
Negative Gaussian Curvature ◽  
Annular Domains ◽  
Spherical Caps ◽  
Local Deformations

We describe shape transitions of thin, solid nematic sheets with smooth, preprogrammed, in-plane director fields patterned across the surface causing spatially inhomogeneous local deformations. A metric description of the local deformations is used to study the intrinsic geometry of the resulting surfaces upon exposure to stimuli such as light and heat. We highlight specific patterns that encode constant Gaussian curvature of prescribed sign and magnitude. We present the first experimental results for such programmed solids, and they qualitatively support theory for both positive and negative Gaussian curvature morphing from flat sheets on stimulation by light or heat. We review logarithmic spiral patterns that generate cone/anti-cone surfaces, and introduce spiral director fields that encode non-localized positive and negative Gaussian curvature on punctured discs, including spherical caps and spherical spindles. Conditions are derived where these cap-like, photomechanically responsive regions can be anchored in inert substrates by designing solutions that ensure compatibility with the geometric constraints imposed by the surrounding media. This integration of such materials is a precondition for their exploitation in new devices. Finally, we consider the radial extension of such director fields to larger sheets using nematic textures defined on annular domains.

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