{"title":"4D printing of pH-responsive bilayer with programmable shape-shifting behaviour","authors":"Smruti Parimita , Amit Kumar , Hariharan Krishnaswamy , Pijush Ghosh","doi":"10.1016/j.eurpolymj.2024.113581","DOIUrl":null,"url":null,"abstract":"<div><div>4D printing of smart materials has seen remarkable advancements in the domain of biomedical devices, with a particular focus on developing responsive and adaptive programmable structures. In this work, we report the 4D printing of two solvent-responsive hydrogels forming a bilayer that undergoes bidirectional actuation depending on the pH of the solvent. A strong interlayer adhesion between the hydrogels is formed without subjecting either of their surfaces to any chemical modification. These hydrogels have an interfacial toughness of 71.8 J/m<sup>2</sup> and undergoes no delamination during actuation inside a solvent. Conventionally, pH-responsive actuators are only limited to simple 2D films prepared by solvent casting. However, our work focuses on the design and fabrication of complex bilayer and patterned structures using Direct-Ink Writing (DIW) approach. These printed structures actuate upon immersion in a solvent medium, and the actuation is reversible in nature. The influence of programmable variables on the morphed structure was studied systematically by modifying the rheological properties (in the range of <span><math><mrow><mn>1</mn><msup><mrow><mn>0</mn></mrow><mrow><mn>2</mn></mrow></msup></mrow></math></span>–<span><math><mrow><mn>1</mn><msup><mrow><mn>0</mn></mrow><mrow><mn>5</mn></mrow></msup></mrow></math></span> Pa s) and printing parameters (optimized at a printing speed of 5 mm/sec, with the extrusion pressure of 5–6 bar and nozzle diameter of 0.5 mm) of the 3D printed bilayer structure. The physicochemical properties of the printable hydrogel ink were tuned such that the same structure can respond to both acidic and basic pH (with non-morphing point at pH 7), by altering the directionality of actuation. We have demonstrated the applications of these pH-responsive actuators in smart valves.</div></div>","PeriodicalId":315,"journal":{"name":"European Polymer Journal","volume":"222 ","pages":"Article 113581"},"PeriodicalIF":5.8000,"publicationDate":"2024-11-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":"0","resultStr":null,"platform":"Semanticscholar","paperid":null,"PeriodicalName":"European Polymer Journal","FirstCategoryId":"92","ListUrlMain":"https://www.sciencedirect.com/science/article/pii/S0014305724008425","RegionNum":2,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":null,"EPubDate":"","PubModel":"","JCR":"Q1","JCRName":"POLYMER SCIENCE","Score":null,"Total":0}
引用次数: 0
Abstract
4D printing of smart materials has seen remarkable advancements in the domain of biomedical devices, with a particular focus on developing responsive and adaptive programmable structures. In this work, we report the 4D printing of two solvent-responsive hydrogels forming a bilayer that undergoes bidirectional actuation depending on the pH of the solvent. A strong interlayer adhesion between the hydrogels is formed without subjecting either of their surfaces to any chemical modification. These hydrogels have an interfacial toughness of 71.8 J/m2 and undergoes no delamination during actuation inside a solvent. Conventionally, pH-responsive actuators are only limited to simple 2D films prepared by solvent casting. However, our work focuses on the design and fabrication of complex bilayer and patterned structures using Direct-Ink Writing (DIW) approach. These printed structures actuate upon immersion in a solvent medium, and the actuation is reversible in nature. The influence of programmable variables on the morphed structure was studied systematically by modifying the rheological properties (in the range of – Pa s) and printing parameters (optimized at a printing speed of 5 mm/sec, with the extrusion pressure of 5–6 bar and nozzle diameter of 0.5 mm) of the 3D printed bilayer structure. The physicochemical properties of the printable hydrogel ink were tuned such that the same structure can respond to both acidic and basic pH (with non-morphing point at pH 7), by altering the directionality of actuation. We have demonstrated the applications of these pH-responsive actuators in smart valves.
期刊介绍:
European Polymer Journal is dedicated to publishing work on fundamental and applied polymer chemistry and macromolecular materials. The journal covers all aspects of polymer synthesis, including polymerization mechanisms and chemical functional transformations, with a focus on novel polymers and the relationships between molecular structure and polymer properties. In addition, we welcome submissions on bio-based or renewable polymers, stimuli-responsive systems and polymer bio-hybrids. European Polymer Journal also publishes research on the biomedical application of polymers, including drug delivery and regenerative medicine. The main scope is covered but not limited to the following core research areas:
Polymer synthesis and functionalization
• Novel synthetic routes for polymerization, functional modification, controlled/living polymerization and precision polymers.
Stimuli-responsive polymers
• Including shape memory and self-healing polymers.
Supramolecular polymers and self-assembly
• Molecular recognition and higher order polymer structures.
Renewable and sustainable polymers
• Bio-based, biodegradable and anti-microbial polymers and polymeric bio-nanocomposites.
Polymers at interfaces and surfaces
• Chemistry and engineering of surfaces with biological relevance, including patterning, antifouling polymers and polymers for membrane applications.
Biomedical applications and nanomedicine
• Polymers for regenerative medicine, drug delivery molecular release and gene therapy
The scope of European Polymer Journal no longer includes Polymer Physics.