Preparation And Application Of Intelligent-responsive Hydrogel Materials

Hydrogels,referred to as a class of crosslinked polymer materials,which have a three-dimensional network structure and possess a large amount of moisture.Since hydrogels are similar in composition to living organisms in nature,they have been widely used in bioengineering,tissue engineering and other research fields.Interestingly,certain hydrogels can respond to external stimuli by certain design or modification to become smart responsive hydrogels,including simple variable temperatures,pH,light and ionic strength.Based on these stimulus-response intelligent systems,intelligent hydrogels are further designed and applied to the field of intelligent bionics and intelligent actuators,which greatly expands the research prospects of hydrogels.This paper designs four different types of intelligent hydrogel systems to promote the applications of smart hydrogel in antifouling/antibateria,sensing platform,and photosensitive materials.The results of the study are summarized as follows:Firstly,a kind of salt-responsive smart polyHEAA hydrogel grafted with polyDVBAPS polymer brushes was prepared by atom transfer radical polymerization?ATRP?,and subsequently AgNPs-loading into the hydrogel network by in situ reduction to obtain“antifouling-sterilization-desorption regeneration”strategy.The results show that this salt-responsive smart hydrogel has nearly 1 week of long-term antifouling and excellent sterilization?>99%?ability through the antibacterial experiments of two model bacteria,E.coli and S.aureus.Just with the treatment by1.0 M NaCl solution,the blocked surface could release the dead/alive bacteria and be reversely regenerated with the influence of“converted from stretch to stretch”from the segment of polyDVBAPS brushes.Remarkably,polyDVBAPS brushes maintains long-term releasing property while reloading AgNPs strategy need to build that offset the irreversible release of AgNPs for keeping an excellent bactericidal ability.Furthermore,a novel intelligent hydrogel-based chemical sensor capable of emittinggreenfluorescencewassuccessfullypreparedbyinsitu adsorption-polymerization-covalent cross-linking method after designing NDBCB monomer.The specific detection of Hg???ions were systematically characterized?including detection kinetics,lower detection limits,and practical applications?.Because both hydrogels and paper-based materials possess porous structure,this hybrid flexible sensor allow for faster capillary forces to drive the aqueous solution itself into the matrix for fast visual inspection compared to conventional rigid counterparts.Moreover,due to superb portability and high sensitivity,rapid visual?green fluorescence into blue fluorescence?detection can indeed be able to realize after about 3 minutes even in complex real-world water systems and food systems.It's probably worth pointing out,the detection limit of this sensor is nearly 8 nM.Smart tunable fluorescent hydrogels are one of the most compelling materials in recent research.Combined with the method of radical polymerization,we further designed hydrophilic three-based-color?red,yellow,blue?fluorescent polymers,and prepared a smart tunable white light hydrogel by physical blending and dynamic chelation effect from Al³⁺ions.The multiple stimuli-responsive properties of hydrogels were explored systematically.Due to the excellent water solubility of multi-color fluorescent polymer material,it allows to achieve color adjustment under the full spectrum by simple blending and expects to be applied to colorful fluorescent inks.Meanwhile,the white-light emission hydrogel effectively realizes the sol-gel transition under the influence of inorganic acid/base,ultrasonic because of the dynamic metal chelation with Al³⁺ions.Furthermore,white-light emission hydrogel can be modified by sodium alginate under the diffusion of Al³⁺ions,which effectively improves its initial mechanical properties.Finally,combined with the hydrophilic fluorescent polymer chain poly?AAm-co-AAc-co-NDBCB?,the semi-interpenetrating fluorescent polyHEAA hydrogel with green light emission was obtained by in-situ polymerization.The semi-interpenetrating structure,influencing factors of the fluorescence properties,and specific detection effect of Hg???were characterized carefully.Interestingly,depending on the designed Hg-responsive thiourea moiety on the fluorescent polymer chain,it can induce a change in the fluorescent color visible from“green to blue”.In addition,the result indicates that UV polymerization has better fluorescence retention and smaller blue-shifting properties than thermal polymerization process.PolyHEAA IPN hydrogel seems to maintain more efficient heavy metal ion visual detection performance in a rich bacterial system compared with polyHEA hydrogel.Moreover,what greatly expands the application of smart hydrogel in the rapid detection of heavy metal ions in water system is that IPN smart hydrogel reveals superb detection limit?⁰.0676?M?and 1 min visual detection time.