Table 1.
XPS determined compositions of the NH2-SAMs on 24nm AuNPs after undergoing a C11 NH2-thiol ligand-exchange with a C2 NH2-SAM for different lengths of time (30min to 61 days). The data was normalized without the Ti signal as discussed in the text.
| Time of Ligand-Exchange |
Atomic % (Std. Dev.) | ||||
|---|---|---|---|---|---|
| C 1s | Au 4f | N1s | O 1s | S 2p | |
| 30min | 23.6 (3.8) | 64.6 (3.1) | 5.3 (0.8) | 2.2 (0.5) | 4.4 (0.4) |
| 3hrs | 23.5 (2.6) | 63.7 (2.4) | 5.4 (0.8) | 2.3 (0.4) | 4.4 (0.5) |
| 12hrs | 25.9 (3.7) | 61.9 (3.6) | 5.4 (0.8) | 2.3 (0.3) | 4.5 (0.4) |
| 24hrs | 27.3 (7.6) | 56.8 (6.0) | 4.2 (1.0) | 2.6 (0.4) | 4.0 (0.5) |
| 2days | 36.2 (5.1) | 52.5 (4.8) | 4.5 (0.4) | 2.8 (0.3) | 4.0 (0.3) |
| 4days | 43.9 (3.9) | 45.7 (4.1) | 4.0 (0.4) | 2.4 (0.3) | 4.0 (0.2) |
| 7days | 47.5 (4.2) | 42.3 (4.0) | 4.2 (0.5) | 2.1 (0.3) | 3.9 (0.4) |
| 14days | 51.3 (2.6) | 37.0 (2.9) | 4.6 (0.4) | 2.9 (0.5) | 3.9 (0.3) |
| 21days | 51.6 (1.2) | 36.4 (0.9) | 4.7 (0.4) | 3.5 (0.6) | 3.6 (0.4) |
| 31days | 50.6 (1.5) | 36.9 (1.3) | 4.8 (0.4) | 3.6 (0.1) | 3.8 (0.3) |
| 61days | 52.3 (1.5) | 35.5 (1.1) | 4.8 (0.3) | 3.3 (0.5) | 3.9 (0.3) |