Facile Fabrication of Multiresponsive Self-Healing Hydrogels with Logic-Gate Responses

Smart hydrogels have received great attention for application in various fields. In this work, the monomers dopamine methacrylamide (DMA) and methacrylamidophenylboronic acid (MAPBA), and the crosslinker bis(methacrylamide) cysteine (BMAC) are first synthesized. The multiresponsive self-healing hydrogels are subsequently prepared by photoinitiation polymerization of the DMA, the MAPBA, the BMAC, and the monomer dimethylaminoethyl methacrylate (DMAEMA) using one-pot method. The dynamic covalent bonds are formed by the reaction of the catechol groups in DMA and phenylboronic acid groups in MAPBA, which contribute as the second crosslinking of the hydrogels besides the BMAC. The hydrogels show pH, temperature, glucose, and redox tetra-responsiveness derived from the reversible dynamic covalent bonds (borate ester and disulfide bonds) and responsive polymer chain PDMAEMA. The hydrogels display gel–sol transition in the presence of HCl and dithiothreitol (DTT) together, which exhibits AND logic gate response. In addition, the hydrogels show excellent self-healing ability due to the well-known dynamic covalent bond of borate esters. This multifunctional and smart hydrogels have potential applications in the fields of sensors, actuators, controlled drug delivery etc.