The WS₂ dependence on the elasticity and optical band gap energies of swollen PAAm composites

Abstract

New generation nano-filler polymer composites have many applications including biomedical, electronic and maritime related applications because of their mechanical, electronic and optical properties. The properties of composites were investigated as a function of nano-filler content. Among these, tungsten disulfide (WS2) has the potential to be used as a component in electronic devices owing to its high electron mobility and easily tunable optical band gap energy. Tungsten disulfide (WS2)- Polyacrylamide (PAAm) composite was prepared using free radical co-polymerization and wet laboratory methods with WS2 content. Composites were characterized for mechanical and optical properties using an Elasticity Instrument and UV-vis Spectrophotometer, respectively. Elastic modulus was modeled by a statistical thermodynamics model. Tauc’s and Urbach’s Tail model for direct transition were used to model for the optical band gap. In this study, the swelling and WS2 effect on the optical band gap and elasticity of WS2 - PAAm composites were investigated. It was observed that the elasticity presented a reversed behavior of optical band gap energies with respect to WS2 content. For the applications of nano-filler doped polymer composites in flexible electronic devices, WS2 content strongly influences the mechanical and optical properties.

Correlation Between Swelling and Elasticity of Graphene Oxide-Polyacrylamide Composites

“…The shear modulus of GO -PAAm composites before and after swelling decrease with the increase of GO content above 8µl GO. It is also known that the swelling properties of composites mainly affect the shear modulus of the composites [1,[14][15][16]. Here it can be seen that the composite has a lower G-value before swelling than after swelling, indicating higher toughness, i.e., high stiffness.…”

“…After reaching the highest shear modulus at 8µl of GO, the shear modulus decreased with increasing GO content. Three contributions were identified, consisting of the degradation of physical cross-links, relaxation common to elastomers and swelling-induced relaxation, to produce the overall stress relaxation of GO -PAAm composites [1,[14][15][16].…”

“…Figure 5a shows the force-compression curves before and after swelling for 40µl of the contents of GO at 30 °C. From the rubber elasticity [14][15][16] the change in the length of the compressed sample, ΔL, is given in equation ( 8) Where is the L 0 original length of the specimen and L is the deformed length of the specimen along the vertical axis. The compressive stress was calculated according to the following equation (9) σ=f/A (9) where f and A are the applied force and the initial crosssectional area of the specimen perpendicular to the direction of loading, respectively.…”

2D Materials (WS2, MoS2, MoSe2) Enhanced Polyacrylamide Gels for Multifunctional Applications

“…On the other hand, the band gap values calculated for MoS 2 /PVP/PAAm composites with different amounts of MoS 2 were found in the range of 3.10–3.81 eV [ 57 ]. The estimated band gap energies of WS 2 /PVP/PAAm composites with various WS 2 contents were between 3.35 and 4.57 eV [ 58 ]. It is observed that the band gap energies of the composites are in good agreement with the previous results.…”

Effect of MWCNT addition on the optical band gap of PVA/CS transient biocomposites

“…The amount, type, size, and shape of the filler in biocomposite can be controlled by changing its physical properties, so it is critical for engineering in the search for new and advanced technologies. 11,25,26 Studying the UV-VIS absorption spectrum of composites is the most direct and simplest method to understand and improve the optical transition, band tail, and band structure. 27 Optical band gap energy knowledge of a composite is required to predict applicability and performance in optoelectronic devices.…”