Bioplastkurs

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Mjuka materia-baserade och kemiskt-drivna aktuatorer

• Utveckling: projektets konceptualisering, brainstorming, designuppställning, syntes av råmaterial.
• Karakterisering: SEM, TEM, AFM, mekanisk testning.
• Dataextraktion, utvärdering och slutsats. 

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I urval från Stockholms universitets publikationsdatabas

• Nanodancing with Moisture: Humidity-Sensitive Bilayer Actuator Derived from Cellulose Nanofibrils and Reduced Graphene Oxide

  2022. Frédéric Héraly (et al.). Advanced Intelligent Systems 4 (1)

  Artikel

  Bilayer actuators, traditionally consisting of two laminated materials, are the most common types of soft or hybrid actuators. Herein, a nanomaterial-based organic–inorganic humidity-sensitive bilayer actuator composed of TEMPO-oxidized cellulose nanofibrils (TCNF-Na⁺) and reduced graphene oxide (rGO) sheets is presented. The hybrid actuator displays a large humidity-driven locomotion with an atypical fast unbending. Cationic exchange of the anionically charged TCNF-Na⁺ and control of the layer thickness is used to tune and dictate the locomotion and actuator's response to humidity variations. Assembly of a self-oscillating electrical circuit, that includes a conductive rGO layer, displays autonomous on-and-off lighting in response to actuation-driven alternating electrical heating.

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• Cationic cellulose Nanofibrils-based electro-actuators: The effects of counteranion and electrolyte

  2023. Frédéric Héraly, Bo Pang, Jiayin Yuan. Sensors and Actuators Reports 5

  Artikel

  Cellulose-based electro-actuators have enormous potential in various applications, e.g. artificial muscles, soft grippers, medical devices, just to name a few, owing to their high mechanical strength, lightness and natural abundance. However, significant challenges remain in the fabrication of such electro-actuators featuring low operating voltage and fast response kinetics. We report here a facile fabrication route towards high-performance electro-actuators composed of CNFs films doped with ionic liquids or lithium salts and sandwiched by two thin film gold electrodes. Large bending motion at voltages as low as 3.0 V could be observed. The size effect of both anions and cations on the actuation was comprehensively investigated. CNF-TFSI@LiTFSI and CNF-BF4@EMIM-BF₄ electro-actuators presented the best bending strain under an AC voltage of 3.0 V. This work provides new inspiration in the design of natural polymer-based high-performance electro-actuators.

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• Vacancy-Rich MXene-Immobilized Ni Single Atoms as a High-Performance Electrocatalyst for the Hydrazine Oxidation Reaction

  2022. Shiqi Zhou (et al.). Advanced Materials 34 (36)

  Artikel

  Single-atom catalysts (SACs), on account of their outstanding catalytic potential, are currently emerging as high-performance materials in the field of heterogeneous catalysis. Constructing a strong interaction between the single atom and its supporting matrix plays a pivotal role. Herein, Ti₃C₂T_x-MXene-supported Ni SACs are reported by using a self-reduction strategy via the assistance of rich Ti vacancies on the Ti₃C₂T_x MXene surface, which act as the trap and anchor sites for individual Ni atoms. The constructed Ni SACs supported by the Ti₃C₂T_x MXene (Ni SACs/Ti₃C₂T_x ) show an ultralow onset potential of −0.03 V (vs reversible hydrogen electrode (RHE)) and an exceptional operational stability toward the hydrazine oxidation reaction (HzOR). Density functional theory calculations suggest a strong coupling of the Ni single atoms and their surrounding C atoms, which optimizes the electronic density of states, increasing the adsorption energy and decreasing the reaction activation energy, thus boosting the electrochemical activity. The results presented here will encourage a wider pursuit of 2D-materials-supported SACs designed by a vacancy-trapping strategy. 

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• A transport channel-regulated MXene membrane via organic phosphonic acids for efficient water permeation

  2021. Ming Yi (et al.). Chemical Communications 57 (51), 6245-6248

  Artikel

  A series of organic phosphonic acids (OPAs) were applied as multifunctional spacers to enlarge the inner space of carbide MXene (Ti3C2Tx) laminates. A synergistic improvement in permeance, rejection and stability is achieved via introducing OPA to create pillared laminates. This strategy provides a universal way to regulate transport channels of MXene-based membranes.

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• Multitasking tartaric-acid-enabled, highly conductive, and stable MXene/conducting polymer composite for ultrafast supercapacitor

  2021. Miao Zhang (et al.). Cell Reports Physical Science 2 (6)

  Artikel

  Ti₃C₂T_x (MXene), a thriving member of the two-dimensional (2D) materials family, has shown increasing potential in a myriad of applications, ranging from printable electronics to energy storage and separation membranes. Nevertheless, the dilemma of its oxidative instability and the easy disintegration of its assemblies in contact with water has been restricting its real-life use. Here, we report the benefits of tartaric acid, a natural source, as a non-innocent additive in the MXene composite. In water, it can, above all, inhibit oxidation of Ti₃C₂T_x and hold individual components in the composite Ti₃C₂T_x/poly(3,4-ethylenedioxy thiophene):polystyrene sulfonate) (Ti₃C₂T_x/PEDOT:PSS) firmly together; equally important, it can boost 4-fold the composite’s electron conductivity in comparison to the additive-free equivalent. To showcase its practical value, a tartaric-acid-treated, water-stable MXene/PEDOT:PSS conductive coating is made, which serves as electrodes for an ultrafast supercapacitor; among all 2D materials-based assemblies, the designed supercapacitor delivers, to our knowledge, the record-high performance in an alternating-current filtering application.

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