The influence of tip sonication on structural and morphological properties of graphene

Although ultrasound is frequently used to disperse carbon nanomaterials in suitable solvents, the propagation of high-amplitude ultrasonic vibrations from the tip sonicator was found to be aggressive and has the potential to break down graphene sheets. Here, the effects of tip sonication time on structural and morphological properties of two types of graphene (graphene oxide and electrochemically exfoliated graphene) was investigated by UV-vis spectroscopy and Atomic Force Microscopy. It was found that the structural composition of the graphene was not affected by ultrasounds emitted from the tip sonicator even for the prolonged period of sonication (60 min). Microscopy analysis showed an increased portion of smaller graphene sheets in the sonicated samples for both types of graphene as a result of graphene sheet fragmentation caused by tip sonication

Graphene oxide-silver nanowires composites for protection against modern pollution - electromagnetic waves

With the development of the electronic industry, telecommunication, transportation, energy storage devices, and wireless technologies, the need for materials that are able to block electromagnetic waves (EMWs) in low-frequency regions of the spectrum is increasing. A new type of pollution named pollution by EMWs is an inevitable component of modern life. Although materials efficient in blocking the propagation of EMWs are developed, these materials show drawbacks regarding durability and mechanical properties, as well as a high production price and processability. Thus, new eco-friendly and durable materials are needed. Herein, we produced composites based on graphene oxide and silver nanowires to create an efficient shielding barrier for low frequencies (0-15 GHz) EMWs

Measurement of EMI shielding performance of graphene oxide and electrochemically exfoliated graphene thin films

Graphene and its derivatives have become the scientific community's focus due to their remarkable electronic, mechanical, and optical properties. In this work, we prepared two graphene-based materials, graphene oxide (GO) and electrochemically exfoliated graphene (EEG), and performed morphological and structural analysis. Both materials showed good dispersibility in water. GO is composed of mainly single- and few-layer graphene sheets, while EEG is predominately multi-layer graphene. EEG showed better thermal stability under nitrogen flow compared to GO. We also performed ElectroMagnetic Interference (EMI) shielding performance measurements of these materials