Synthesis and mesomorphic properties of side‐chain liquid crystalline ionomers containing sulfonic acid groups

Abstract

Side-chain liquid crystalline ionomers containing M 1 (4-allyoxybenzoyloxy-4 0 -amylbenzoyloxy biphenyl) as mesogenic units and M 2 (4-undecylenicoxy-4 0 -phenylazobenzene sulfonic acid) as ionic units were synthesized by graft copolymerization. Their liquid crystalline properties were characterized by differential scanning calorimetry, polarizing optical microscopy, and X-ray diffraction measurements. The results showed that introduction of nonmesogenic ionic units into polymeric structure could cause additional reduction of the clearing point of the ionomers, compared with the corresponding nonion polymers. When the content of ionic units increased to 8.5%, the ionic clusters and mesogens in the ionomers may be dispersed each other to form multiple blocks, but the introduction of ionic groups in LCIs did not change their mesogenic type.

Correspondence between the rigid amorphous fraction and nanoconfinement effects on glass formation

“…Consistent with some evidence in the RAF, the size of altered‐mobility domains near other polymer interfaces tends to grow on cooling . Of particular similarity to the case of the RAF is the emergence of a suppressed mobility region around ionic aggregates in ionomers . As in semicrystalline polymers, this region was long believed to fundamentally emerge from covalent connectivity between amorphous polymer and crystalline or rigid ionic aggregates—a model proposed by Eisenberg in a parallel body of literature to contemporaneous work on semicrystalline polymers .…”

Glass Formation near Covalently Grafted Interfaces: Ionomers as a Model Case

“…For example, ionomersion-containing polymersexhibit strong spatial gradients in segmental dynamics near interfaces between charged ionic aggregates that are characteristic of their morphology and the surrounding neutral monomer domains, with the covalent bonds between the aggregated ionic moieties and attached neutral chain segments serving as trans-interfacial grafts (for example, see Figure for a snapshot of a simulated such interface from the present study). This effect also generally yields an enhancement in the ionomer’s overall segmental relaxation time and glass transition temperature, T g , − and can introduce an additional high-temperature relaxation process that is sometimes termed a “second T g ”. − ,− Similarly, semicrystalline polymers frequently exhibit a “rigid amorphous fraction” of material with suppressed segmental dynamics, with this observation commonly being associated with the presence of dangling or bridging amorphous chains that are effectively grafted to the surface of crystalline domains. In both cases, these phenomena can profoundly alter transport and mechanical properties.…”

Cholesteric Cyclohexane-Containing Side-Chain Liquid-Crystalline Polysiloxanes

“…Side-chain liquid crystalline polymers (SCLCPs) belong to one branch of LCPs, and have attracted great attention in the field of academia and engineering, mainly because they exhibit both particularly electro-optical properties of low molecular weight liquid crystals and favorable mechanical properties of polymer. [1][2][3][4][5][6][7] From 1980 several SCLCPs were researched. In recent years, research into LCPs has expanded rapidly, and monomers or polymers with Cholesteric phases have attracted considerable interest because they have outstanding optical properties.…”