Diblock copolymers directing construction of hierarchically porous metal-organic frameworks for enhanced-performance supercapacitors

Abstract

A rationally designed strategy is developed to synthesize hierarchically porous Fe-based metal-organic frameworks (P-Fe-MOF) via solution-based self-assembly of diblock copolymers. The well-chosen amphiphilic diblock copolymers (BCP) of polystyrene-block-poly(acrylic acid) (PS-b-PAA) exhibits outstanding tolerance capability of rigorous conditions (e.g. strong acidity or basicity, high temperature and pressure), steering the peripheral crystallization of Fe-based MOF by anchoring ferric ions with outer PAA block. Importantly, the introduction of BCP endows MOF materials with additional mesopores (∼40 nm) penetrating whole crystals, along with their inherent micropores and introduced macropores. The unique hierarchically porous architecture contributes to fast charge transport and electrolyte ion diffusion, and thus promotes their redox reaction kinetics processes. Accordingly, the resultant P-Fe-MOF material as a new electrode material for supercapacitors delivers the unprecedented highest specific capacitance up to 78.3 mAh g−1 at a current density of 1 A g−1, which is 9.8 times than that of Fe-based MOF/carbon nanotubes composite electrode reported previously. This study may inspire new design of porous metal coordination polymers and advanced electrode materials for energy storage and conversion field.

Synthesis, Hydrophilicity and Micellization of Coil-Brush Polystyrene-b-(polyglycidol-g-polyglycidol) Copolymer—Comparison with Linear Polystyrene-b-polyglycidol

“…Similarly, chemical shifts in 13 C NMR spectra of the signals of carbon atoms in PS-b-(PGL-g-PGL) copolymers confirmed their coil-brush structure. It should be noted that in 13 C NMR spectra Figure 1b) the main signals b, c, and d are accompanied with the weaker ones corresponding to atoms of the end groups of the grafts. It is also worth stressing that polymerization degrees of all synthesized copolymers determined by 1 H NMR were close to DP n values calculated from compositions of polymerization mixtures (see Table 1).…”

“…Figure 1a,b shows representative 1 H and 13 C NMR spectra of final PS-b-(PGL-g-PGL)1 copolymer sample (see Table 1) confirming its chemical structure.…”

“…1 H and 13 C NMR spectra of intermediate products obtained after each step of synthesis and of the final coil-brush PS-b-(PGL-g-PGL) block copolymer were registered using a Bruker (200 MHz) NMR spectrometer. The PS-OH sample and block copolymers with protected hydroxyl groups were dissolved in CDCl 3 , whereas diblock copolymers with free hydroxyls were dissolved in DMSO.…”

“…Amphiphilic block copolymers (BCPs) have found numerous applications in various fields of science and branches of industry such as drug delivery carriers [1][2][3][4][5], bioactive agents carriers [6,7], tissue engineering materials [8], electrochemical sensors [9], polymer blends [10], polymer membranes [11], nanoreactors with embedded enzymes [12], enhanced-performance supercapacitors [13], anti-bacterial and anti-protein fouling coatings of various materials [14][15][16], surfactants systems for stabilization of various emulsions [17], and polymer solar cells [18]. The final application of copolymers is closely related to the chemical structure, architecture of macromolecules and properties of blocks components.…”

“…For both copolymer classes, the DP n of the polystyrene block was the same at 29 (the same polystyrene sample with the anionic end-groups was used as macroinitiator for synthesis of polyglycidol containing blocks). For both classes, the number of polyglycidol units in macromolecules varied in the range from 13…”