Solid Polymer Electrolytes with Excellent High-Temperature Properties Based on Brush Block Copolymers Having Rigid Side Chains

Abstract

A series of brush block copolymers (BBCPs) with polynorbornene backbones containing poly{2,5-bis[(4-methoxyphenyl)oxycarbonyl]styrene} (PMPCS, which is a rigid chain) and poly(ethylene oxide) (PEO) side chains were synthesized by tandem ring-opening metathesis polymerizations. The weight fractions of PEO in BBCPs are similar, and the degrees of polymerization (DPs) of PEO side chains are the same while the DPs of PMPCS are different. The bulk self-assembling behaviors were studied by small-angle X-ray scattering (SAXS). The neat BBCPs cannot form ordered nanostructures. However, after the doping of lithium salt, the BBCPs self-assemble into lamellar (LAM) structures. When the DPs of the PEO and PMPCS side chains are similar, the LAM structure is more ordered, which is attributed to the more flat interface between PMPCS and PEO phases. The ionic conductivity (σ) values of the BBCP/lithium salt complex with the most ordered LAM structure at different temperatures were measured. The σ value increases with increasing temperature in the range of 40-200 °C, and the relationship between σ and T fits the Vogel-Tamman-Fulcher (VTF) equation. The σ value at 200 °C is 1.58 × 10 S/cm, which is one of the highest values for PEO-based polymer electrolytes. These materials with high σ values at high temperatures may be used in high-temperature lithium ion batteries.

Controllable Cross‐Linking Anion Exchange Membranes with Excellent Mechanical and Thermal Properties

“…Anion exchange membranes (AEMs), a kind of ion exchange membrane with selective permeability, have the function of blocking gas, cations, and conducting anions, and can be used in fuel cells, liquid flow cells, and so on . In order to meet the requirements of practical applications, AEMs need to have good ion conductivity, strong mechanical properties, high‐dimensional stability, and other comprehensive performance .…”

Grubbs’ and Schrock’s Catalysts, Ring Opening Metathesis Polymerization and Molecular Brushes—Synthesis, Characterization, Properties and Applications

“…The covalent attachment of drug molecules on the PEO side chains or as a separate block on the main chain has also been employed for drug delivery purposes [78,79,80,81,82,83,84]. Other small molecules serving a specific function have also been covalently bonded on the PEO side chains or in umbrella-like structures [72,73,74,85,86,87,88,89,90,91,92,93,94,95,96]. In some cases, more complex structures have been synthesized, depending on the needs of applications, or for academic interest.…”

“…Pseudo-alternating structures with one PEO polymeric chain and a small molecule (drug or others) on each monomeric unit have been synthesized for high (bio)technology materials: PEO-doxorubicin [78,84], PEO-camptothecin [78], PEO-triethylene glycol [99]. Molecular brushes with umbrella-like structure (Figure 4F) have been prepared with a variety of norbornene derivatives for specialized purposes [79,83,87,88,90,91,92,93,94,100]. Core–shell structures (Figure 4E) have been synthesized with PS- b -PEO, PEO- b -PS [27] diblock side chains.…”

“…Apart from the aforementioned medical-biological applications, bottlebrushes with PEO segments have been synthesized and studied as potential materials for various applications. Fan and his team have studied the potential of molecular brushes to be used as high-temperature lithium ion batteries [92]. On the same track, Grubbs, Jones and their coworkers have investigated the ionic conductivity of PS- b -PEO- b -PS triblock molecular brushes doped with lithium bis(trifluoromethane)-sulfonimide [61].…”

Polysiloxane-Based Side Chain Liquid Crystal Polymers: From Synthesis to Structure–Phase Transition Behavior Relationships

“…Oligo(oxyethylene)s groups, which exhibit polarity, flexibility, hydrophilicity, low toxicity, and the ability to form complexation with Li + , have an important position in the field of physical chemistry and other scientific research, and have been used in molecular engineering of rigid rod-like conjugated polymer systems in order to improve solubility in hydrophilic solvents [146], or to obtain “hairy rod” polymers for polymer electrolyte applications [147,148,149].…”