Fluorescent carbazole oligomers nanofibril materials for vapor sensing
A fluorescence based sensor ( 10 ) is disclosed and described. The sensor ( 10 ) can include nanofibril materials ( 12 ) fabricated from a linear carbazole oligomer and a fluorescence detector ( 14 ). The linear carbazole oligomer can have the formula (I) wherein n is 3 to 9, R are independently selected amine sidegroups, and at least one, but not all, R is a C1 to C14 alkyl. The carbazole-based fluorescence based sensors ( 10 ) can be particularly suitable for detection of explosives and volatile nitro compounds.
1. A fluorescence based sensor comprising:
a) nanofibrils of a linear carbazole oligomer having the formula
wherein n is 3 to 9, R are independently selected amine sidegroups, and at least one, but not all, R is a C1 to C14 alkyl; and
b) a fluorescence detector.
2. The sensor of claim 1 , wherein the at least one R is selected from the group consisting of linear alkyl, branched alkyl, cyclic alkyl, and combinations thereof.
3. The sensor of claim 1 , wherein the at least one R is octyl.
4. The sensor of claim 1 , wherein n is 3.
5. The sensor of claim 4 , wherein a first R is H, a second R is octyl and a third R is H such that the linear carbazole oligomer is
6. The sensor of claim 1 , wherein at least one R is H.
7. The sensor of claim 1 , wherein the nanofibrils have a diameter of about 10 nm to about 100 nm.
8. The sensor of claim 1 , wherein the linear carbazole oligomer nanofibrils are formed as a film.
9. The sensor of claim 1 , wherein the fluorescence detector is a fluorimeter.
10. A method of detecting explosives and quinones, comprising:
a) exposing nanofibrils formed from a linear carbazole oligomer to a target sample, said linear carbazole oligomer having the formula
wherein n is 3 to 9, R are independently selected amine sidegroups, and at least one, but not all, R is a C1 to C14 alkyl; and
b) measuring fluorescence responses of the linear carbazole oligomer nanofibrils.
11. The method of claim 10 , further comprising displaying an explosives indicator based on the fluorescence responses.
12. The method of claim 11 , wherein the explosives indicator is a quantitative measurement.
13. The method of claim 11 , wherein the explosives indicator is a qualitative measurement.
14. The method of claim 10 , wherein the at least one R is selected from the group consisting of linear alkyl, branched alkyl, cyclic alkyl, and combinations thereof.
15. The method of claim 10 , wherein the at least one R is octyl.
16. The method of claim 10 , wherein n is 3.
17. The method of claim 16 , wherein a first R is H, a second R is octyl and a third R is H such that the linear carbazole oligomer is
18. The method of claim 10 , wherein at least one R is H.
19. The method of claim 10 , wherein the linear carbazole oligomer nanofibrils have a diameter of about 10 nm to about 100 nm.
20. The method of claim 10 , wherein the linear carbazole oligomer nanofibrils are formed as a film.
21. The method of claim 10 , wherein the target sample is a nitroaromatic explosive or a nitroaliphatic explosive.
22. The method of claim 21 , wherein the fluorescence responses are statistically significant at target sample concentrations of about 5 ppb and greater.