A general study of the adsorption of n-alkanes in the flexible metal organic framework (MOF) MIL-53 is presented. The roles of the length of the alkyl chain (n = 1-9), the nature of the metal (Al, Cr), and temperature were investigated. The shape of the adsorption curves is driven by the alkyl chain length of the n-alkanes. While traditional type-I isotherms are observed for short alkanes (n = 1, 2), adsorbates with longer chains induce clear substeps in the isotherm curves whose positions depend on the chain length. Such substeps are due to a breathing phenomenon, as proven by ex situ X-ray diffraction analysis. They strongly depend on the amount of adsorbate in the pores and on the nature of the metal (Al, Cr), which, for a given alkane, leads to a strong change in the substep positions despite the similar characteristics of the two metals. The adsorption kinetics are highly sensitive to small variations in temperature. Their detailed analysis in different regions of the isotherms shows in some cases the existence of distinct diffusion regimes and/or conformations within the flexible phases.

Abstract. One-step functionalization of alginate with boronic acid groups allowed spontaneous formation of biocompatible hydrogels under basic conditions without additional complementary molecules or crosslinking agents. The dynamic nature of boronate ester bonds formed with vicinal diols present on alginate pyranose rings provided remarkable self-healing, injectable and multi-stimuli responsive properties to the material.Stimuli-responsive hydrogels are characterized by the ability to respond to external triggers (e.g. pH, temperature, light, specific molecules, etc.), a major property typically associated with their potential use for biomedical applications.1,2 In addition, the development of biomimetic gelbased materials with self-healing properties has extended their prospect for new applications. Nature relies on the use of reversible sacrificial bonds that allow for a better adaptation of a biomaterial to specific environments as well as for self-reparation upon damage. [3][4][5][6] This has inspired an emerging research area devoted to the fabrication of self-healable hydrogel networks based on dynamic covalent chemistry. [7][8][9] In sharp contrast to covalently crosslinked hydrogels, whose stable bonds do not undergo exchange reactions, gels based on dynamic bonds are able to reform bonds around a damaged zone, allowing the restitution of their functional properties. 9Within this context, boronic acids have been extensively studied due to their excellent ability to interact reversibly with diols, forming boronate