Influence of Polymer Matrix on Polymer/Graphene Oxide Nanocomposite Intrinsic Properties

Abstract

Electrically conductive polymer nanocomposite films comprising reduced graphene oxide (rGO) have been prepared using aqueous emulsion-based techniques with a specific focus on the effects of the polymer matrix. Polymer matrices with glass transition temperatures in a suitable range were selected such that film formation can occur at ambient temperature via drop-casting of the as-obtained nanocomposite latexes. The monomers methyl methacrylate (MMA), benzyl methacrylate (BzMA), and styrene (St) were each copolymerized with n-butyl acrylate (nBA) using radical polymerization implemented as miniemulsion polymerization or soap-free emulsion polymerization. Thermal annealing of the films converted GO to rGO, thus imparting electrical conductivity. In agreement with theoretical calculations related to the propensity of GO sheets to operate as Pickering stabilizers based on polarity and interfacial tension, nanocomposites with higher electrical conductivity resulted for monomers of lower polarity such as nBA/St and nBA/ BzMA compared to the more polar system nBA/MMA. Incorporation of GO resulted in higher Young's modulus and more brittle materials regardless of the polymer matrix. The results demonstrate that relatively subtle changes in the nature of the polymer matrix can have significant effects on nanocomposite properties.

Polymer/Reduced Graphene Oxide/Lignosulfonate Nanocomposite Films as Pseudocapacitor Cathodes

“…For example, the presence of peaks, such as 1728, 1455, and ∼700–760 cm –1 , was a contribution from P­( n BA- stat -BzMA)/rGO, whereas peaks at 3375, 1571, 1396, 1000–1100, and 617 cm –1 can be assigned to the contribution from LS (Figure f). Raman analysis of the films, as shown in Figure g, exhibits characteristic D and G peaks of rGO at approximately ∼1353 and 1586 cm –1 , respectively, similar to the previously published reports. , The presence of D and G peaks corresponds to the degree of structural defects in the carbon lattice and sp 2 -hybridized carbon cluster in the lattice, respectively . Further analysis of the D and G peaks in terms of their intensity ratios calculated from the deconvolution and Lorentzian fitting of the two peaks revealed a minor reduction in ( I D / I G ) values for P­( n BA- stat -BzMA)/rGO/LS (0.71) compared to the P­( n BA- stat -BzMA)/rGO film (0.77), which was in agreement with I D /I G values observed previously for similar thermally reduced nanocomposites. ,, The reason behind the observed marginal reduction in the I D / I G values with the inclusion of LS is not entirely clear.…”

“…Raman analysis of the films, as shown in Figure 3g, exhibits characteristic D and G peaks of rGO at approximately ∼1353 and 1586 cm −1 , respectively, similar to the previously published reports. 1,45 The presence of D and G peaks corresponds to the degree of structural defects in the carbon lattice and sp 2 -hybridized carbon cluster in the lattice, respectively. 46 Further analysis of the D and G peaks in terms of their intensity ratios calculated from the deconvolution and Lorentzian fitting of the two peaks revealed a minor reduction in (I D /I G ) values for P(nBA-stat-BzMA)/rGO/LS (0.71) compared to the P(nBA-stat-BzMA)/rGO film (0.77), which was in agreement with I D /I G values observed previously for similar thermally reduced nanocomposites.…”

“…The obtained values were in agreement with previous reports on similar nanocomposite films in terms of the composition and preparation method. 45,47 Next, nanocomposite films casted on a silicon mold were subjected to DMA to determine their mechanical properties. We observed significant reduction in mechanical behavior as adjudged by the significant systematic reduction in the strain at break with the inclusion of fillers (GO and LS) (Figure S1, Supporting Information).…”

In Situ Surfactant Effects on Polymer/Reduced Graphene Oxide Nanocomposite Films: Implications for Coating and Biomedical Applications

“…To impart electrical conductivity, polymer/GO nanocomposite films prepared on glass slides were subjected to heat treatment at 160 °C for 24 h in an air-cooled oven, which has previously shown by us to effectively reduce GO to rGO. − …”

Synthesis of Highly Stretchable and Electrically Conductive Multiwalled Carbon Nanotube/Polymer Nanocomposite Films

“…Solution mixing and melt processing have been the most common methods for synthesizing CNT/polymer nanocomposites. , However, solution mixing normally involves the use of toxic volatile organic solvents, melt mixing is a highly energy intensive technique, and aggregation is still a serious issue even at lower concentrations of CNTs using these methods. ,− On the other hand, latex technology has received less focus to date even though it is more environmentally friendly, easier to control, and can often provide more uniform distribution and dispersibility of CNTs within the polymer matrix compared to other techniques. ,, In latex technology, an aqueous dispersion of the filler and polymer latex prepared from emulsion-based polymerization techniques are mixed together or the filler dispersion can be used in situ with the synthesis of the polymer latex. Taking graphene-based materials like graphene oxide as an example, it has been widely used as a surfactant in emulsion-based polymerization techniques, − and aqueous dispersions of graphene derivatives can be mixed with a variety of polymer matrices to fabricate highly functional and conductive nanocomposites. ,− Since the structure of CNT is generally a cylindrical graphene sheet, it is of interest to investigate how homogeneous distribution of CNT, especially at higher CNT contents, can be achieved using such emulsion-based techniques and thus improved nanocomposite properties.…”