Functionalized Cellulose Nanocrystal-Mediated Conjugated Polymer Aggregation

Abstract

Inducing the self-assembly of π-conjugated polymers into semicrystalline aggregates has been a topic of substantial interest in the field of organic electronics and is typically achieved using energy-intensive solution processing or postfilm deposition methods. Here, we demonstrate the ability of bioderived cellulose nanocrystals (CNCs) to act as structure-directing agents for the conjugated semiconducting polymer, poly­(3-hexylthiophene) (P3HT). CNCs were grafted with polystyrene, P3HT or poly­(N-isopropylacrylamide), and subsequently blended with P3HT in solution to study the effect on conjugated polymer self-assembly. The presence of polymer-grafted CNCs resulted in an increase in P3HT semicrystalline aggregate formation, the degree of which depended on the surface free energy of the grafted polymer. The time-dependent P3HT aggregation was characterized by UV–vis spectroscopy, and the resulting data was fit to the Avrami crystallization model. The surface energies of each additive were calculated via contact angle measurements and were used to elucidate the mechanism of P3HT aggregation in these blended systems. P3HT aggregation was enhanced by unfavorable polymer–polymer interactions at the CNC surface, and spatial confinement effects that were imposed by phase separation. Finally, films were cast from the P3HT/CNC solutions and their electronic performance was characterized by organic field-effect transistor device measurements. Films containing polymer-grafted CNCs exhibited higher charge-carrier mobilities, in some cases, up to a 6-fold increase. These bioderived particles constituted a significant volume fraction of the deposited P3HT thin films with an increase in performance, showing promise as a method for reducing costs and improving the sustainability of organic electronics.

Active Material Interfacial Chemistry and Its Impact on Composite Magnetite Electrodes

“…To directly attach PPBT onto the surface of the magnetite nanoparticles, a scheme commonly found in the functionalization of carboxylic-containing molecules onto CNCs was used. 24 First, 500 mg of Fe 3 O 4 nanoparticles were dispersed in 60 mL of deionized water with an ultrasonic probe (3 pulses of 30 s each, operated at 50 W, Qsonica Q700 sonicator). The Fe 3 O 4 dispersion was then transferred to a 100 mL round-bottom flask fitted with a magnetic stir bar.…”

Grafting polymers from cellulose nanocrystals via surface‐initiated atom transfer radical polymerization

“…Hollow silica nanorods with accessible micro‐ and meso‐pores were then subsequently obtained, after calcination of the hybrid nanomaterial. In a completely different area, polystyrene‐ and PNIPAM‐grafted CNC prepared by ATRP were used as structure‐directing agents for poly(3‐hexylthiophene (P3HT), in order to improve the optoelectronic performances of this conjugated semi‐conducting polymer 217 . The presence of the hybrid nanoparticles in P3HT solutions (chloroform) resulted in an increase in P3HT semi‐crystalline aggregate formation, due to unfavorable polymer–polymer interactions at the surface of the CNC, and spatial confinement effects imposed by phase separation.…”

“…In a completely different area, polystyreneand PNIPAM-grafted CNC prepared by ATRP were used as structure-directing agents for poly(3-hexylthiophene (P3HT), in order to improve the optoelectronic performances of this conjugated semi-conducting polymer. 217 The presence of the hybrid nanoparticles in P3HT solutions (chloroform) resulted in an increase in P3HT semi-crystalline aggregate formation, due to unfavorable polymer-polymer interactions at the surface of the CNC, and spatial confinement effects imposed by phase separation. The electronic performances of films casted from the P3HT blends were then characterized by organic fieldeffect transistor measurements.…”

Influence of side‐chain isomerization on the isothermal crystallization kinetics of poly(3‐alkylthiophenes)

“…Nevertheless, few attempts have been made with conventional DSC [12,13]. In addition to the pure P3AT systems, crystallization kinetics have also been investigated for blend systems [23,24,25] and block copolymers [26,27,28,29,30,31,32,33]. Müller et al investigated the crystallization of P3HT-polyethylene (PE) diblock copolymer, they found that the crystal growth of P3HT block and PE block remains unaffected: onedimensional for P3HT and spherulitic growth for PE [27].…”