Cross-linked conjugated polymer fibrils: Robust nanowires from functional polythiophene diblock copolymers

Article abstract of DOI:10.1021/cm2018345

A series of poly(3-hexyl thiophene) (P3HT)-based diblock copolymers were prepared and examined in solution for their assembly into fibrils, and post-assembly cross-linking into robust nanowire structures. P3HT-b-poly(3-methanol thiophene) (P3MT), and P3HT-b-poly(3-aminopropyloxymethyl thiophene) (P3AmT) diblock copolymers were synthesized using Grignard metathesis (GRIM) polymerization. Fibrils formed from solution assembly of these copolymers are thus decorated with hydroxyl and amine functionality, and cross-linking is achieved by reaction of diisocyanates with the hydroxyl and amine groups. A variety of cross-linked structures, characterized by transmission electron microscopy (TEM), were produced by this method, including dense fibrillar sheets, fibril bundles, or predominately individual fibrils, depending on the chosen reaction conditions. In solution, the cross-linked fibrils maintained their characteristic vibronic structure in solvents that would normally disrupt (dissolve) the structures.

Full text of DOI:10.1021/cm2018345

Supporting Information
Cross-linked Conjugated Polymer Fibrils: Robust Nanowires from
Functional Polythiophene Diblock Copolymers
Brenton A. G. Hammer, Felicia Bokel, Ryan C. Hayward,* and Todd Emrick*
Polymer Science and Engineering Department, 120 Governors Drive University of Massachusetts, Amherst, MA
01003
tsemrick@mail.pse.umass.edu; rhayward@mail.pse.umass.edu
A
B
80
70
60
50
40
30
20
10
0
P3HT
190
170
150
130
110
90
P3HT
P3HT-b-P3THPT
P3HT-b-P3MT
P3HT-b-P3BPT
P3HT-b-P3AmT
70
50
20
22
24
26
28
30
20
22
24
26
28
30
Time (min)
Time (min)
Figure S1: Gel permeation chromatographs of A) P3HT, P3HT-b-PTHPT, and P3HT-b-P3MT and B) P3HT,
P3HT-b-P3BPT, and P3HT-b-P3AmT diblock copolymers with chloroform as the eluent against PS standards
Table S1: Molecular weights of P3THPT (6) and P3BPT (7) homopolymers
PDIb
1.40
1.50
Entry Polymer # Mn(Theor.) (g/mol)a Mn(Exper.) (g/mol)b
1
2
6
7
10,000
12,000
8,650
7,900

a From monomer to catalyst ratio. b Estimated by GPC against PS standards.
Free P3HT
Free P3HT-b-P3MT
0.18
0.16
Free P3HT-b-P3AmT
0.14
0.12
0.1
0.08
0.06
0.04
0.02
0
300
400
500
600
700
Wavelength (nm)
Figure 2S: UV-vis spectra of A) free P3HT, P3HT-b-P3MT, and P3HT-b-P3AmT in chloroform
B
A
C
D
100 nm
Figure 3S: TEM images of aged A) fibrillar sheets (P3HT-b-P3AmT) B) fibrillar bundles (P3HT-b-P3AmT) C)
discrete fibrils (P3HT-b-P3AmT) and D) thermally annealed fibrillar bundles (P3HT-b-P3AmT) drop cast from
10mg/mL chloroform solution