Supramolecular materials, dynamic materials by nature, are defined as materials whose components are bridged via reversible connections and undergo spontaneous and continuous assembly/disassembly processes under specific conditions. On account of the dynamic and reversible nature of noncovalent interactions, supramolecular polymers have the ability to adapt to their environment and possess a wide range of intriguing properties, such as degradability, shape-memory, and self-healing, making them unique candidates for supramolecular materials. In this critical review, we address recent developments in supramolecular polymeric materials, which can respond to appropriate external stimuli at the fundamental level due to the existence of noncovalent interactions of the building blocks.

Introduction 7399 2. Synthesis of Rotaxanes Based on Various Macrocycles 7400 2.1. Crown Ethers 7401 2.1.1. Bis(m-phenylene)-32-crown-10 and Crown Ethers with Larger Sizes 7401 2.1.2. Dibenzo-24-crown-8 7402 2.1.3. Benzo-21-crown-7 7406 2.1.4. Crown Ether-Based Cryptands 7407 2.2. Cyclodextrins 7410 2.3. Cucurbiturils 7413 2.3.1. Cucurbit[6]uril 7413 2.3.2. Cucurbit[7]uril 7414 2.3.3. Cucurbit[8]uril 7415 2.4. Calixarenes 7416 2.4.1. Calix[4]arenes as Linkers or Stoppers 7416 2.4.2. Calix[5]arenes and Calix[6]arenes as Wheels 7416 2.4.3. Heterocalix[n]arenes or Calix[n]heteroarenes 7417 2.5. Pillararenes 7418 2.5.1.

Herein, we report a de novo chemical design of supramolecular polymer materials (SPMs-1-3) by condensation polymerization, consisting of (i) soft polymeric chains (polytetramethylene glycol and tetraethylene glycol) and (ii) strong and reversible quadruple H-bonding cross-linkers (from 0 to 30 mol %). The former contributes to the formation of the soft domain of the SPMs, and the latter furnishes the SPMs with desirable mechanical properties, thereby producing soft, stretchable, yet tough elastomers. The resulting SPM-2 was observed to be highly stretchable (up to 17 000% strain), tough (fracture energy ∼30 000 J/m), and self-healing, which are highly desirable properties and are superior to previously reported elastomers and tough hydrogels. Furthermore, a gold, thin film electrode deposited on this SPM substrate retains its conductivity and combines high stretchability (∼400%), fracture/notch insensitivity, self-healing, and good interfacial adhesion with the gold film. Again, these properties are all highly complementary to commonly used polydimethylsiloxane-based thin film metal electrodes. Last, we proceed to demonstrate the practical utility of our fabricated electrode via both in vivo and in vitro measurements of electromyography signals. This fundamental understanding obtained from the investigation of these SPMs will facilitate the progress of intelligent soft materials and flexible electronics.

Light-emitting materials, especially those with tunable wavelengths, attract considerable attention for applications in optoelectronic devices, fluorescent probes, sensors and so on. Many species evaluated for these purposes either emit as a dilute solution or on aggregation, with the former often self-quenching at high concentrations, and the latter falling dark when aggregation is disrupted. Here we preserve emissive behaviour at both low- and high-concentration regimes for two discrete supramolecular coordination complexes (SCCs). These tetragonal prismatic SCCs are self-assembled on mixing a metal acceptor, Pt(PEt3)2(OSO2CF3)2, with two organic donors, a pyridyl-decorated tetraphenylethylene and one of two benzene dicarboxylate species. The rigid organization of these fluorescence-active ligands imparts an emissive behaviour to dilute solutions of the resulting assemblies. Furthermore, on aggregation the prisms exhibit variable-wavelength visible-light emission, including rare white-light emission in tetrahydrofuran. The favourable photophysical properties and solvent-dependent aggregation behaviour provide a means to tune emission wavelengths.