Table 3.

A brief record of epoxy-based nanocomposites studied for improvement in electrical conductivity values. HSM: high speed mixing.

Sr.	Authors	Year	Reinforcement/wt %	Dispersion method	% Increase in electrical conductivity	Remarks	Ref.
1	Wu et al.	2015	GNPs (1.5 wt %), transverse to alignment	Sn + 3RM	1 × 107	The maximum thermal conductivity was observed in the case of aligned GNPs.	[229]
			GNPs (3 wt %), randomly oriented		1 × 108
			GNPs (3 wt %), parallel to alignment		1 × 1010
2	Liu et al.	2015	Graphene woven fabric (GWF) (0.62 wt %)	None.	1 × 1013	(Samples were produced using resin infiltration.) The average number of graphene layers in GWFs varied between 4 and 12.	[230]
3	Ming et al.	2015	Graphene foam (GF) (80 wt %)	None.	8 × 102	(Samples were produced using hot pressing.) The electrical conductivity of pure graphene foam (GF) is 2.9 S-cm-1, which is much lower than graphene, which can be because of the presence of structural defects.	[231]
5	Ghaleb et al.	2014	GNPs (1.1 wt %)	Sn	1.39 × 106	GNPs are more effective in improving the thermal conductivity of epoxy than MWCNTs.	[159]
			MWCNTs (1.9 wt %)		1.62 × 105
6	Tang et al.	2014	GO (5 wt %)	Sn + HSM	1.92 × 109	The surface functionalization of GO can significantly improve the electrical conductivity of GO–epoxy.	[232]
			Diamine polyetheramine functionalized GO (GO-D230) (5 wt %)		1.92 × 1012
7	Dou et al.	2014	Silver plated graphene (Ag-G) (25 wt %)	Sn + MS	4.13 × 102	Ag–graphene can be used in electronic applications due to its high electrical conductivity.	[233]
8	Tang et al.	2014	GO (3.6 wt %)	Sn	1 × 1018	The surface functionalization significantly improves electrical conductivity.	[234]
			Polyetheramine refluxed GO (GO-D2000) (3.6 wt %)		1 × 1017
9	Monti et al.	2013	GNPs (3 wt %)	Sn + MS	2.08 × 105	The samples were produced using chloroform.	[235]
			GNPs (3 wt %)		1.16 × 105	The samples were produced using tetrahydrofuran.
10	Wajid et al.	2013	GNPs (0.24 wt %)	Sn + MS	2.22 × 103	The samples were produced using dimethylformamide.	[189]
11	Chandrakekaran et al.	2013	GNPs (1 wt %)	Sn + ShM	1 × 104	3RM is more effective in improving the electrical conductivity of epoxy than sonication and high speed shear mixing.	[73]
			GNPs (2 wt %)	3RM	1 × 108
12	Suherman et al.	2013	GNPs (80 wt %), CNTs (5 wt %), through-plane	BM + MS	7.30 × 1017	The electrical conductivity significantly increases with hybrid filler.	[236]
			GNPs (80 wt %), CNTs (5 wt %), in-plane		1.80 × 1018
			GNPs (80 wt %), through-plane		4 × 1017
			GNPs (80 wt %) in-plane		5 × 1017
13	Mancinelli et al.	2013	GO (0.5 wt %)	Sn	240	The conductivity was measured before post-curing.	[237]
			GO (0.5 wt %)		730	The conductivity was measured after post-curing.
			Octadecylamine (ODA)-treated partially reduced and chemically modified GO (MGO) (0.5 wt %)		550	The conductivity was reduced after functionalization.
			GO (0.5 wt %)	Two phase extraction	240	The system was not fully cured during curing process.
			GO (0.5 wt %)		7.80 × 103	The conductivity significantly increased after post-curing.
14	Al-Ghamdi et al.	2013	Foliated graphite nanosheets (FGNs) (40 wt %)	Centrifugal mixing	9.90 × 103	Dielectric properties of epoxy–FGN composites decreased with an increase in frequency.	[238]
15	Kim et al.	2012	Al(OH)3 functionalized GO (Al-GO) (3 wt %)	MS + MgSr	75	The increase in electrical conductivity decreases with Al(OH)3 functionalization of GO.	[239]
			GO (3 wt %)		115
16	Heo et al.	2012	Al2O3 (80 wt %), Al(OH)3 functionalized GO (Al-GO) (5 wt %)	3RM	2.90 × 103	The increase in electrical conductivity with Al(OH)3 functionalization decreased. The electrically insulating Al(OH)3 on the graphene oxide nanosheet can prevent electron tunneling and act as ion traps which block ion mobility, resulting in a decrease in the electrical properties of nanocomposites.	[224]
			Al2O3 (80 wt %), GO (5 wt %)		4.90 × 103
17	Tien et al.	2011	Graphite flakes (14 wt %)	Sn	4 × 107	The percolation threshold was 8 wt %.	[227]
18	Fan et al.	2009	GNPs (5 wt %)	Sn + MS	5.50 × 1010	The maximum electrical conductivity was observed in the case of hybrid fillers.	[240]
			GNPs (4.5 wt %), carbon black (CB) (0.5 wt %)		5.50 × 1012
19	Jovic et al.	2008	Expanded graphite (EG) (8 wt %)	Sn	5.50 × 1017	The electrical conductivity further increases with the application of electric field.	[241]
20	Li et al.	2007	MWCNTs (1 wt %)	Sn	4.63 × 107	The samples were produced using acetone.	[242]
21	Pecastaings et al.	2004	MWCNTs (20 wt %)	Sn + MS	4.53 × 103	The samples were produced using acetone.	[243]