Page 9 - MSAM-2-2

Materials Science in Additive Manufacturing Union of 2D nanomaterials and 3D printing

lattice structure consisting of a single sp -layer of hybridized of the oxygen-containing functional groups from the
2
carbon atoms. Graphene comprises a tightly arranged graphene surface . It is possible to obtain rGO using
[24]
hexagonal honeycomb structure of carbon atoms, where several methods: hydrothermal , solvothermal , flash
[25]
[26]
covalent bonds connect each of them to three adjoined reduction , chemical, and photocatalytic approaches .
[28]
[27]
atoms via a σ bond . Mechanical stripping, liquid-phase rGO, containing fewer oxygen functional groups, surface
[16]
stripping , electrochemical dissolution , chemical charge, and hydrophilic groups than GO, can also be
[17]
[18]
vapor deposition , epitaxy , and organic synthesis are assembled through non-covalent interactions, including
[21]
[20]
[19]
commonly utilized. Due to its strictly 2D structure, graphene π-π stacking and van der Waals forces, making it
displays exclusive thermal, electrical, and mechanical effective for biomolecule adsorption. Some studies have
properties, thus presenting tremendous potential for various demonstrated that rGO has excellent cytocompatibility
[29]
technical applications. Notably, graphene has a considerable and electrical conductivity , therefore is widely used in
[30]
theoretical specific surface area, high thermal conductivity, biosensing, microfluidics, and tissue engineering [31-33] .
high intrinsic mobility, high optical transmittance, high
Young’s modulus, and excellent electrical conductivity. 2.1.4. Black phosphorus (BP)
Graphene-based membranes are impervious to all liquids and BP is a unique allotrope of the chemical element
gases, highlighting their exceptional physicochemical and phosphorus, with a layered structure composed of
biological properties and their potential for various scientific individual atoms sheets held together by weak van der
applications. The emergence of graphene-based materials Waals forces. The structure of BP consists of a hexagonal
has already led to their use in numerous fields, including lattice of phosphorus atoms that are covalently bonded
tissue engineering, bioelectronics, cancer treatment, drug to each other, with each atom having three neighboring
delivery, antibacterial materials development, gene delivery, atoms . The sheets are stacked on top of each other to
[34]
biosensing, and other biomedical applications. form a 3D structure. Each layer is a single atom thick, and
the layers are held together by weak van der Waals forces,
2.1.2. Graphene oxide (GO) which allow for easy exfoliation of the material into thinner
GO is a chemically altered structure of graphene, which is layers . BP can be synthesized using various methods,
[35]
typically produced by oxidizing and exfoliating graphite including high-pressure/high-temperature techniques,
through the incorporation of oxygen functional groups such chemical vapor deposition, and liquid-phase exfoliation .
[36]
as epoxy (-O), carboxyl (-OOH), or hydroxyl (-OH) on their High-pressure/high-temperature techniques involve
basal planes and edges. The modified Hummers’ method is heating red phosphorus under high pressure to convert it
considered the leading technique for producing GO . The to BP. Chemical vapor deposition involves the deposition
[22]
exceptional characteristics of GO surfaces stem from their of phosphorus vapor onto a substrate under controlled
non-covalent interactions with other surfaces and molecules in conditions, while liquid-phase exfoliation involves the
solution, including hydrophobic effects, π-π stacking, charge exfoliation of BP flakes from a liquid dispersion. The
interactions, and hydrogen bonding. These characteristics distinctive electronic and optical properties of BP enable it
make GO a highly appealing platform for cellular delivery to possess a broad spectrum of prospective applications .
[37]
applications. The hydrophilicity and colloidal stability of It has been studied for use in electronic and optoelectronic
GO are increased due to its negatively charged carboxylate devices, such as field-effect transistors, photodetectors,
groups, which, in turn, promote surface proliferation and and solar cells [38-40] . Its high carrier mobility, strong light-
differentiation of neurocytes. Physical interactions and matter interactions, and anisotropic electrical and optical
surface reactions can be induced by the uncharged epoxide properties make it particularly promising for these
and hydroxyl groups on the basal plane of GO. In addition, applications. BP is also being investigated for energy
the non-functionalized areas on the basal planes are water- storage, sensing, and biomedical applications [41-44] .
repellent, allowing for π-π interactions, and making GO a
commonly recommended amphiphilic material. The oxygen- 2.1.5. Laponite
containing functional groups on GO render it hydrophilic, Laponite (i.e., nanoclay) is a synthetic clay mineral used
making it highly useful in drug delivery, biosensors, and in a variety of industrial and commercial applications [45-48] .
tissue engineering. GO also exhibits unique electrochemical Laponite comprises disk-shaped particles containing a
properties, including high thermal conductivity, chemical central alumina-silicate platelet enveloped by charged
inertness, optical transmittance, and high current density . hydroxyl groups with thickness and diameter ranging from
[23]
1 to 25 nanometers (nm) [49,50] . The charged hydroxyl groups
2.1.3. Reduced GO (rGO) on the surface of the particles allow easy dispersion in water
rGO is derived from GO through a reduction process and other solvents , making laponite a useful additive in
[51]
and features structural defects while maintaining part a variety of applications. Laponite is typically synthesized

Volume 2 Issue 2 (2023) 3 https://doi.org/10.36922/msam.0620