Dynamic Coordination of Eu–Iminodiacetate to Control Fluorochromic Response of Polymer Hydrogels to Multistimuli

Abstract

New fluorochromic materials that reversibly change their emission properties in response to their environment are of interest for the development of sensors and light-emitting materials. A new design of Eu-containing polymer hydrogels showing fast self-healing and tunable fluorochromic properties in response to five different stimuli, including pH, temperature, metal ions, sonication, and force, is reported. The polymer hydrogels are fabricated using Eu-iminodiacetate (IDA) coordination in a hydrophilic poly(N,N-dimethylacrylamide) matrix. Dynamic metal-ligand coordination allows reversible formation and disruption of hydrogel networks under various stimuli which makes hydrogels self-healable and injectable. Such hydrogels show interesting switchable ON/OFF luminescence along with the sol-gel transition through the reversible formation and dissociation of Eu-IDA complexes upon various stimuli. It is demonstrated that Eu-containing hydrogels display fast and reversible mechanochromic response as well in hydrogels having interpenetrating polymer network. Those multistimuli responsive fluorochromic hydrogels illustrate a new pathway to make smart optical materials, particularly for biological sensors where multistimuli response is required.

An Adaptable Tough Elastomer with Moisture‐Triggered Switchable Mechanical and Fluorescent Properties

“…For example, Eu complexes can pick up trace amount of water from organic solvents, which has been widely studied for water detection on the basis of the fluorescence quenching . By incorporating red‐emissive Eu 3+ ions in the polymer matrix, others and our group have shown that the responsiveness of polymers can modulate the fluorescent emission of Eu 3+ ions 4b,9a,12. In the current contribution, the dynamic coordination of Eu‐iminodiacetate (IDA) as a key component is used to build up the physical cross‐linking network in the polymer film consisting of interpenetrating polymer network (IPN) ( Figure a).…”

Poly(vinyl alcohol)–Carbon Nanodots Fluorescent Hydrogel with Superior Mechanical Properties and Sensitive to Detection of Iron(III) Ions

“…The change in the storage modulus ( G ′) and the loss modulus ( G″ ) was recorded by the strain amplitude test (γ, 1–1000%). The step strain test was performed for three cycles at 1 HZ, which was converted from small strain (γ = 1%, 100 s for each interval) to large strain (γ = 900%, 100 s for each interval) . All photographic images come from the camera (Canon EOS 600D).…”

Bioinspired Healable Mechanochromic Function from Fluorescent Polyurethane Composite Film

“…A superhydrophobic and mechanically durable biomimicking material was created by combining characteristics of the lotus leaf, mussel, and sandcastle worm . Multifunctional materials with mechanical sensing and self‐healing under magnetic fields and multistimuli were reported. The development of multifunctional materials that integrate mechanochromic and self‐healing properties is highly demanded.…”