Supramolecular polymer networks are non-covalently crosslinked soft materials that exhibit unique mechanical features such as self-healing, high toughness and stretchability. Previous studies have focused on optimising such properties using fast-dissociative crosslinks (i.e. for aqueous system, k d > 10 s -1 ). Herein, we describe non-covalent crosslinkers with slow, tuneable dissociation kinetics (k d < 1 s -1 ) that enable high compressibility to supramolecular polymer networks. The resultant glass-like supramolecular networks have compressive strengths up to 100 MPa with no fracture, even when compressed at 93% strain over 12 cycles of compression and relaxation. Notably, these networks show a fast, room-temperature self-recovery (< 120 s), which may be useful for the design of high-performance soft materials. Retarding the dissociation kinetics of non-covalent crosslinks through structural control enables access of such glass-like supramolecular materials, holding significant promise in applications including soft robotics, tissue engineering and wearable bioelectronics.Supramolecular polymer networks (SPNs) are a class of soft materials composed of linear polymers transiently crosslinked through non-covalent interactions. 1, 2 On account of the dynamic nature of these crosslinks, they can serve as sacrificial bonds to dissipate applied energy, thus imparting SPNs with remarkable material properties including high toughness, 3 enhanced damping capacity, 4 extreme stretchability, 5-7 rapid self-healing 8-10 , and reversible mouldability. 11 These superior material properties have lead to the use of SPNs as repairable electrodes, 12, 13 artificial skins, 14,15 and drug-delivery devices 16,17 . Although promising strides have been made, the material requirements for some demanding applications have not yet been met. A major limitation of SPNs is achieving extreme compressibility with ultra-high compressive strength and complete self-recovery on short time scales.Comparing covalently to non-covalently crosslinked polymers, the dissociation kinetics for dynamic networks plays a critical role in the material design and mechanical properties of the SPNs. 1 Craig and co-workers revealed that it is in fact crosslink dynamics, rather than equilibrium thermodynamics, that are paramount in determining the material properties (e.g. viscoelasticity) of SPNs. 18,19 They reported that slower dissociation kinetics resulted in more intact crosslinks within a transient network under an applied force, leading to a higher complex modulus. Holten-Anderson et al. further demonstrated control over hierarchical polymer mechanics through tuning the relative ratio of two kinetically-distinct metal-ligand crosslinks, which allowed for decoupling of the material mechanics from crosslink structure. 20 These pioneering reports established the basis for understanding the relationship between crosslink kinetics and SPN material properties.

Metal−organic framework nanoparticles (nanoMOFs) have been widely studied in biomedical applications. Although substantial efforts have been devoted to the development of biocompatible approaches, the requirement of tedious synthetic steps, toxic reagents, and limitations on the shelf life of nanoparticles in solution are still significant barriers to their translation to clinical use. In this work, we propose a new postsynthetic modification of nanoMOFs with phosphate-functionalized methoxy polyethylene glycol (mPEG− PO 3 ) groups which, when combined with lyophilization, leads to the formation of redispersible solid materials. This approach can serve as a facile and general formulation method for the storage of bare or drugloaded nanoMOFs. The obtained PEGylated nanoMOFs show stable hydrodynamic diameters, improved colloidal stability, and delayed drug-release kinetics compared to their parent nanoMOFs. Ex situ characterization and computational studies reveal that PEGylation of PCN-222 proceeds in a two-step fashion. Most importantly, the lyophilized, PEGylated nanoMOFs can be completely redispersed in water, avoiding common aggregation issues that have limited the use of MOFs in the biomedical field to the wet forma critical limitation for their translation to clinical use as these materials can now be stored as dried samples. The in vitro performance of the addition of mPEG−PO 3 was confirmed by the improved intracellular stability and delayed drug-release capability, including lower cytotoxicity compared with that of the bare nanoMOFs. Furthermore, z-stack confocal microscopy images reveal the colocalization of bare and PEGylated nanoMOFs. This research highlights a facile PEGylation method with mPEG−PO 3 , providing new insights into the design of promising nanocarriers for drug delivery.

‘Trojan Horse’ anionic poly(methacrylic acid)–poly(benzyl methacrylate) vesicles enable efficient incorporation of either nanoparticles or soluble small molecules within calcite.

We describe the 3-iodopropyl acetal moiety as a simple cleavable unit that undergoes acid catalyzed hydrolysis to liberate HI (pK a ∼ −10) and acrolein stoichiometrically. Integrating this unit into linear and network polymers gives a class of macromolecules that undergo a new mechanism of degradation with an acid amplified, sigmoidal rate. This trigger-responsive self-amplified degradable polymer undergoes accelerated rate of degradation and agent release.

Phenyl-perfluorophenyl polar−π interactions have been revisited for the design and fabrication of functional supramolecular systems. The relatively weak associative interactions (ΔG ≈ −1.0 kcal/mol) have limited their use in aqueous selfassembly to date. Herein, we propose a strategy to strengthen phenyl-perfluorophenyl polar−π interactions by encapsulation within a synthetic host, thus increasing the binding affinity to ΔG= −15.5 kcal/mol upon formation of heteroternary complexes through social self-sorting. These heteroternary complexes were used as dynamic, yet strong, cross-linkers in the fabrication of supramolecular gels, which exhibited excellent viscoelasticity, stretchability, self-recovery, self-healing, and energy dissipation. This work unveils a general approach to exploit host-enhanced polar−π interactions in the design of robust aqueous supramolecular systems.