Page 129 - Polymer-based Nanocomposites for Energy and Environmental Applications

Energy and environmental 4

applications of graphene and its
derivatives

N. Saba, M. Jawaid
Universiti Putra Malaysia, Serdang, Malaysia

4.1 Introduction

Graphene is a novel, atomically thin two-dimensional (2-D) carbonaceous material
that has received tremendous attention in the scientific community due to its unique
and specific properties [1]. A single layer of graphene was first obtained in 2004 by the
isolation of graphene from graphite via micromechanical cleavage [1]. Graphene
is regarded as the building block for allotropes of carbonaceous materials such as
fullerenes, CNTs, and graphite [2,3], of different dimensions, as it can be produced
and processed at low cost [2]. Several techniques have now been explored to isolate
inexpensive graphene from low-cost graphite with no metallic impurity by exfoliation
of graphite [4]. The single-layer graphene, bilayer graphene, multilayer graphene,
graphene oxide (GO), reduced graphene oxide (RGO), and chemically modified
graphene are widely used graphene nanofibers (GFNs). Graphene and its basic
derivative are shown in Fig. 4.1. GO is an analog of graphene with many functional
groups and possesses different chemical and physical properties from those of
graphene. Graphene, sometimes treated as RGO, easily synthesized from GO [5].
Each member of GFNs markedly differs in terms of oxygen content, purity, surface
chemistry, number of layers, lateral dimensions, defect density, and composition [3].
Graphene also exists in the form of graphene nanoplatelets (GNPs), consisting
of small stacks of graphene. They easily get agglomerate due to van der Waals
interactions and are typically >15 layers thick [6] (Fig. 4.2), with advantageous
properties of graphene [7]. They can replace carbon nanotubes, carbon fiber, and
nanoclays in many composite applications. Addition of 2–5 wt% of GNPs to plastics
or resins improves the electric, thermal conductivity and mechanical properties like
strength, stiffness, or surface toughness but reduces the gas permeability. GNPs
are extremely useful as nanoscale additives for strong and impermeable packaging,
resistive heaters, lubricants, advanced composites, advanced batteries electrodes
[8], ultra-/supercapacitors, e-inks or printable electronic circuits components, and
specialty coatings or adhesives conductive component (https://www.cheaptubes.
com/product-category/graphene-nanoplatelets). GNPs are also found suitable for
biotechnology, medicine applications, and electrochemical detection such as
NP-decorated cholesterol sensors, nanocomposite cancer sensors, detectors of

Polymer-based Nanocomposites for Energy and Environmental Applications. https://doi.org/10.1016/B978-0-08-102262-7.00004-0
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