Table 2.

Thermal conductivity of graphene base nanofluids with respect to ultrasonication period.

NANOPARTICLE	CONCENTRATION	SONICATION DETAILS	SURFACTANTS	THERMAL CONDUCTIVITY				REFERENCES
				30 ˚C	40 ˚C	50 ˚C	60 ˚C
Graphene	0.05%	Stirring & 30 mins ultrasonication vibration	SDBS	0.705	0.727	0.76	N/A	[109]
	0.1%			0.725	0.765	0.805
	0.15%			0.785	0.825	0.877
Graphene nanoplatelets	0.1 wt%	60 mins ultrasonication	SDS	0.559	0.618	N/A		[110]
			CTAB	0.635	0.648
			SDBS	0.64	0.66
			Gum Arabic	0.645	0.676
Graphene nanoplatelets	0.01 wt%	10 mins sonication	–	0.31	0.34	0.36	0.37	[70]
	0.05 wt%			0.38	0.4	0.41	0.42
	0.1 wt%			0.43	0.44	0.45	0.46
	0.2 wt%			0.46	0.48	0.5	0.52
Graphene	0.05%	30–45 mins	–	1.02	1.019	1.03	N/A	[73]
	0.08%			1.052	1.066	1.078
Graphene oxide	0.1 wt%	40mins sonication	SDS	0.63	0.65	N/A		[75]
			Triton X-100	0.62	0.64
Graphene	0.124%	45mins sonication	Not used	0.315	0.318	0.319	0.325	[76]
	0.207%			0.324	0.327	0.33	0.339
	0.395%			0.335	0.339	0.342	0.345
Graphene nanoplatelets	0.02 wt%	Magnetic stirring 10hrs, 5hrs sonication	Gum acacia	0.63	0.66	N/A		[83]
	0.1 wt%			0.72	0.77
Carboxyl graphene	0.04%	40 mins stirring, 9 h sonication	SDS	N/A	0.373	0.395	N/A	[1 1 1]
Graphene nanoparticles (750 m2/g)	0.025 wt%	Probe sonicator 1200 W ,20 kHz	Not used	0.68	0.71	N/A		[106]
	0.05 wt%			0.71	0.75
	0.1 wt%			0.75	0.8
Graphene NP-Ag	0.2%	Ultrasonication bath-3hrs	Not used/Acid treatment	0.63	0.651	N/A		[1 1 2]
	1.0%			0.72	0.77
Graphene nano-platelets	0.1%	20 mins stirring, 10mins sonication	NPE 400 (ionic)	0.5	0.51	0.525	N/A	[85]
	0.2%			0.54	0.55	0.565
	0.3%			0.62	0.64	0.66
Graphene nanoplatelets	0.01%	30mins sonication	Gum Arabic	0.63	0.64	0.657	0.663	[1 1 3]
	0.05%			0.64	0.642	0.67	0.682
	0.1%			0.641	0.68	0.7	0.712
Graphene nanoplatelets	0.1%	70 mins	Not used	0.187	0.18	0.179	0.17	[82]
	0.25%			0.20	0.20	0.199	0.19
	0.5%			0.215	0.213	0.21	0.209
Graphene	0.3%	40 mins	SDS	0.586	0.606	N/A		[81]
	0.05%			0.626	0.636
				0.611	0.62
	0.1%		SDBS	0.605	0.613
				0.613	0.617
				0.610	0.6175
Graphene nanoparticles	0.25 wt%	240mins sonication bath with vibrations	SDBS	0.40	0.405	0.419	0.42	[80]
	0.5 wt%			0.41	0.415	0.421	0.43
	1.0 wt%			0.42	0.425	0.435	0.44