Nanocellulose/Fullerene Hybrid Films Assembled at the Air/Water Interface as Promising Functional Materials for Photo-electrocatalysis

Abstract

Cellulose nanomaterials have been widely investigated in the last decade, unveiling attractive properties for emerging applications. The ability of sulfated cellulose nanocrystals (CNCs) to guide the supramolecular organization of amphiphilic fullerene derivatives at the air/water interface has been recently highlighted. Here, we further investigated the assembly of Langmuir hybrid films that are based on the electrostatic interaction between cationic fulleropyrrolidines deposited at the air/water interface and anionic CNCs dispersed in the subphase, assessing the influence of additional negatively charged species that are dissolved in the water phase. By means of isotherm acquisition and spectroscopic measurements, we demonstrated that a tetra-sulfonated porphyrin, which was introduced in the subphase as anionic competitor, strongly inhibited the binding of CNCs to the floating fullerene layer. Nevertheless, despite the strong inhibition by anionic molecules, the mutual interaction between fulleropyrrolidines at the interface and the CNCs led to the assembly of robust hybrid films, which could be efficiently transferred onto solid substrates. Interestingly, ITO-electrodes that were modified with five-layer hybrid films exhibited enhanced electrical capacitance and produced anodic photocurrents at 0.4 V vs Ag/AgCl, whose intensity (230 nA/cm2) proved to be four times higher than the one that was observed with the sole fullerene derivative (60 nA/cm2).

Nanocellulose for Paper and Textile Coating: The Importance of Surface Chemistry

“…An anionic exchange in favor of the sulfated CNCs generated a floating fulleropyrrolidine/CNCs bilayer. Horizontal transfer of the bilayers onto ITO electrodes yielded photoresponsive films with enhanced performances with respect to electrodes modified by deposition of the sole fulleropyrrolidine [162,200] . Figure 12 shows AFM topographies of 2D films of the sole fulleropyrrolidine and a fulleropyrrolidine/CNCs bilayer, evidencing the 2D‐organization of CNCs induced by the cationic counterpart.…”

“…Horizontal transfer of the bilayers onto ITO electrodes yielded photoresponsive films with enhanced performances with respect to electrodes modified by deposition of the sole fulleropyrrolidine. [162,200] Figure 12 shows AFM topographies of 2D films of the sole fulleropyrrolidine and a fulleropyrrolidine/ CNCs bilayer, evidencing the 2D-organization of CNCs induced by the cationic counterpart. More generally, layer-by-layer techniques were identified as ideal methods to produce selforganized CNCs thin films from their water dispersions, possessing a 2D organization, which may be of interest for antireflection coatings.…”

Tailoring the Chemical Structure of Cellulose Nanocrystals by Amine Functionalization

“…[1] The interest towards these nanostructures is high, considering the plethora of applications that can be envisioned for these sustainable nanoparticles. [4][5][6][7][8][9][10][11] Only recently, CNCs application in Cultural Heritage preservation and conservation was proposed and investigated. [12][13][14][15][16][17][18][19] In particular, cellulose nanocrystals have revealed great potential as protection and reinforcing agents for historical paper [12][13][14] and canvases.…”

“…Discovered in the 1950s, [2,3] CNCs can be isolated by acid hydrolysis using sulfuric, phosphoric or halogenidric acids [1] . The interest towards these nanostructures is high, considering the plethora of applications that can be envisioned for these sustainable nanoparticles [4–11] …”

Reductive Amination Reaction for the Functionalization of Cellulose Nanocrystals

“…Siding the industrially oriented research, new emerging fields of application of nanocellulose include hydrogels and aerogels [ 13 , 14 ], emulsion stabilizers [ 15 ], biocatalyst immobilizers [ 16 ], biosensors [ 17 ], drug delivery systems [ 18 ], adsorbents for contaminants [ 19 , 20 ], nanocomposites for environmental remediation [ 21 ], photonic films and transparent substrates for optoelectronic devices, as well as new nanostructured electroactive materials [ 22 , 23 , 24 , 25 , 26 ].…”