Table 3.

Characterization using a Knudsen flow reactor of the surface functional groups present on the multi-walled carbon nanotubes (MWCNT)

MWCNT	Gas [gas-phase probe molecules]	N(CH3)3 [acidic sites]	HCl [basic sites]	CF3COOH [basic sites]	NH2OH [carbonyl functions]	O3 [oxidisable sites]	NO2 [oxidisable sites]
NT1	N°/mga	3.0 · 1015	8.1 · 1016	2.4 · 1016	2.4 · 1017	3.9 · 1018	1.2 · 1016
	N°/cm2b	1.32 · 1012	35.6 · 1012	10.6 · 1012	105.5 · 1012	1715 · 1012	5.3 · 1012
NT2	N°/mga	6.4 · 1015	4.4 · 1016	5.9 · 1015	3.4 · 1017	1.8 · 1017	1.2 · 1015
	N°/cm2b	11.8 · 1012	81.3 · 1012	1.1 · 1012	628.5 · 1012	332.7 · 1012	2.2 · 1012
NT3	N°/mga	2.6 · 1014	1.4 · 1016	5.8 · 1014	2.0 · 1017	1.1 · 1018	1.9 · 1015
	N°/cm2b	0.8 · 1012	41.2 · 1012	1.7 · 1012	588 · 1012	3235 · 1012	5.6 · 1012

^a Number of probe molecules taken up per mg of deposited nanoparticles.

^b Number of probe molecules taken up per square cm of MWCNT (no/cm²), using the BET surface as a surface metric.

NT1, uncoated MWCNT; NT2, MWCNT coated with carboxylic polyacid polymer; NT3, MWCNT coated with polystyrene polybutadiene polymethylacrylate polymer.