Neither Fluorocarbons nor Silicones:Hydrocarbon-Based Water-Borne Healable Supramolecular Elastomer with Unprecedent Dual Resistance to Water and Organic Solvents

Except for fluorocarbons and silicones,few artificial materials display both water and organic solvent resistance.Herein,we report an artificial hydrocarbonbased supramolecular elastomer that displays unprecedented dual resistance to both water and organic solvents.This elastomer is formed in water with two water soluble components,folic acid(FA)and branched poly(ethylene imine)(b-PEI).The hydrogen bonding between the two components occurs immediately,which further promotes the hydrogen bonding between the FA,yielding folate quartets and theirπ-πstacking.These multiple noncovalent interactions work synergistically,leading to a hydrophobic,transparent,stretchable,healable,notchinsensitive,and recyclable elastomer that resists both water and organic solvents.The elastomer remains intact after storage in high humidity and organic solvents for months.Films generated by stretching the elastomer are very hydrophobic,and the contact angle of water on the elastomer is up to 112.3°.The damaged elastomers also exhibit water-assisted healable behavior.This work discloses a new paradigm of material synthesis that can inspire the fabrication of robust nonfluorocarbon and silicone-based materials with green strategies.

Solid-phase molecular self-assembly facilitated supramolecular films with alternative hydrophobic/hydrophilic domains for skin moisture detection

Human skin moisture is closely related to health and personal care issues.Many creams were developed to claim capable of skin moisturizing.However,people can hardly check their skin moisture status and the moisturizing effect of various creams conveniently,since currently all the skin moisturizing detection rely on large equipment requiring power supply.Herein,we report a power-supply independent supramolecular film that is able to directly report the moisturizing status of the skin.With the strategy of solid-phase molecular self-assembly(SPMSA),the aqueous precipitates formed by commercially available polyelectrolyte and oppositely charged surfactant would transform into a supramolecular film under a mild mechanical pressure,where the hydrophobic surfactant domains bridged by polyelectrolyte merge into hydrophobic mesophases to reduce interfacial energy.The hydrophobic mesophase will greatly retard water diffusion inside the film,so that a humidity gradient is generated as the film is exposed to a humid environment.The film will bend upward automatically in touch with moisture skin,and the bending degree is proportional to the skin moisture status.Therefore,the film can be used as portable smart power-free skin moisture sensor.