Highly Enhanced Vapor Sensing of Multiwalled Carbon Nanotube Network Sensors by n-Butylamine Functionalization

Table 1

Sensor responses and of sensors with pristine and functionalized MWCNT, respectively, to concentration pulses of different VOC in air from a broad range of polarities defined by Hansen solubility parameters , , and and total Hildebrand solubility parameter, .

Solvent	MPa^1/2]	MPa^1/2]	MPa^1/2]	MPa^1/2]	%]	%]	%]
n-Pentane	14.5	0	0	14.5	8.0	10	25.0
n-Heptane	15.3	0	0	15.3	6.5	8.0	23.1
Diisopropyl ether	13.8	2.8	4.6	14.8	8.4	12.3	46.4
Diethyl ether	15.5	2.9	4.6	16.4	8.5	17.0	100.0
Ethyl acetate	15.8	5.3	7.2	18.2	9.3	22.0	136.6
2-Butanone	16.0	9.0	5.1	19.1	8.2	26.3	220.7
Chloroform	15.3	18.0	6.1	24.4	4.6	20.5	345.7
1-Pentanol	16.0	6.8	17.4	24.6	5.0	28.0	460.0
Methanol	15.1	12.3	22.3	29.6	3.8	35.8	842.1