Publications by authors named "Germercy Paredes"
Understanding the origin of the dissipative mechanisms that control the dynamics of a contact line is a real challenge. In order to study the energy dissipation at the contact line when a moving meniscus encounters topographical defects, we developed atomic force microscopy (AFM) experiments using nanofibers with nanometer scale defects. These experiments realized with three liquids are performed in two AFM modes: the contact mode (C-AFM) is used to measure the energy associated with the contact angle hysteresis in the limit of a static situation, deduced from advancing and receding dipping experiments on an isolated defect; the frequency-modulation mode (FM-AFM) is performed at different amplitudes and then velocities to measure the energy dissipated as the contact line moves over the same defect.
View Article and Find Full Text PDFArticle Synopsis
- Researchers developed new types of probes made from all-graphenic carbon morphologies attached to individual carbon nanotubes, which may enhance scanning probe microscopy (SPM) techniques.
- They tested three methods for mounting these probes, two involving focused ion/electron beams and one using an optical microscope, highlighting the pros and cons of each method.
- Analysis showed the carbon cone structures were highly sensitive to ion and electron irradiation, likely due to many free graphene edges, suggesting that these carbon cones could outperform traditional probes like silicon or diamond in SPM applications.
Article Synopsis
- - The study involves creating graphene-based carbon micro/nano-cones using a chemical vapor deposition method on carbon nanotubes and examining them with advanced microscopy and modeling techniques.
- - The results showed that the cones have a scroll-like texture, with parallel scroll turns and a common helicity vector, allowing for possible coherent stacking despite curvature-induced lattice shifts.
- - A unique graphene termination defect, termed the "zip" defect, was identified at the cone apexes, leading to a low Raman band ratio, and the findings contributed to a chart categorizing various defects affecting graphene structures.