| 1. |
- Chang, Jian, 1990-
(författare)
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Processing 2D nanomaterials into inorganic-polymer composite films and fibers with well-defined properties
- 2023
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- 2D materials such as graphene, graphene oxide (GO), reduced graphene oxide (rGO) and MXene, possess unique properties, e.g., high carrier mobilities, mechanical flexibility, good thermal conductivity, and high optical and UV adsorption. They are potentially applicable in the fields of electronics, optoelectronics, catalysts, energy storage facilities, sensors, solar cells, lithium batteries, and so on. Normally, weak interactions and irregular packing or stacking of 2D layers may adversely offset or weaken to some extent their 2D effects such as mechanical and electrical properties at a macroscale. In this regard, it is required to spatially organize 2D materials into macroscopic forms of a well-defined shape (e.g. fibers, films, or 3D structures) in a way that can simultaneously preserve favorable 2D properties and functions shown at the nanoscale, and facilitate their compatibility with the state-of-the-art industrial processes. In my thesis, different types of 2D materials, here GO, rGO and MXene together with polymers were rationally assembled into functional composite materials. The synergistic molecular crosslinking strategy was utilized and controlled in such composite materials for the sake of better performance. My thesis mainly involves four parts: (1) Tough and strong GO composite films via a polycationitrile approach. The interface between GO nanosheets was reinforced via an intermolecular covalent crosslinking approach called “polycationitrile chemistry”. As a result, the mechanical performance of the as-prepared GO-based composite films was enhanced and maintained even at an extremely high relative humidity of 98%.(2) rGO-poly(ionic liquid) (PIL) composite films with high mechanical performance. The rGO/PIL composite films were designed and fabricated, where the synergistic supramolecular interactions between PIL and rGO layer enable high electrical conductivity and favorable mechanical properties.(3) Regenerated cellulose (RC)/MXene composite nanofibers for personal heating management. I harnessed a biodegradable RC-based fibrous matrix to bond with inorganic MXene nanoflakes via electrospinning method. Via hybridization, the as-formed RC/MXene nanofibers present a promotion of mechanical performance and photothermal conversion capability. As a personal heating cloth, it realizes energy-saving outdoor thermoregulatory.(4) RC/MXene solar absorber for solar-driven interfacial water evaporation. The RC/MXene composite nanofibers integrate considerable merits of excellent mechanical performance, wettability, and fast steam generation rate. The RC/MXene solar absorber offers significant values for the practical application of solar-driven steam generation.
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| 2. |
- Chang, Jian, 1990-, et al.
(författare)
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Tailor-Made White Photothermal Fabrics : A Bridge between Pragmatism and Aesthetic
- 2023
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Ingår i: Advanced Materials. - : Wiley. - 0935-9648 .- 1521-4095. ; 35:41
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Tidskriftsartikel (refereegranskat)abstract
- Maintaining human thermal comfort in the cold outdoors is crucial for diverse outdoor activities, e.g., sports and recreation, healthcare, and special occupations. To date, advanced clothes are employed to collect solar energy as a heat source to stand cold climates, while their dull dark photothermal coating may hinder pragmatism in outdoor environments and visual sense considering fashion. Herein, tailor-made white webs with strong photothermal effect are proposed. With the embedding of cesium–tungsten bronze (CsxWO3) nanoparticles (NPs) as additive inside nylon nanofibers, these webs are capable of drawing both near-infrared (NIR) and ultraviolet (UV) light in sunlight for heating. Their exceptional photothermal conversion capability enables 2.5–10.5 °C greater warmth than that of a commercial sweatshirt of six times greater thickness under different climates. Remarkably, this smart fabric can increase its photothermal conversion efficiency in a wet state. It is optimal for fast sweat or water evaporation at human comfort temperature (38.5 °C) under sunlight, and its role in thermoregulation is equally important to avoid excess heat loss in wilderness survival. Obviously, this smart web with considerable merits of shape retention, softness, safety, breathability, washability, and on-demand coloration provides a revolutionary solution to realize energy-saving outdoor thermoregulation and simultaneously satisfy the needs of fashion and aesthetics.
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| 3. |
- Fan, Zhiwen, et al.
(författare)
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Porous Ionic Network/CNT Composite Separator as a Polysulfide Snaring Shield for High Performance Lithium–Sulfur Battery
- 2023
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Ingår i: Macromolecular rapid communications. - 1022-1336 .- 1521-3927. ; 44:24
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Tidskriftsartikel (refereegranskat)abstract
- Lithium–sulfur (Li–S) battery features a high theoretical energy density, but the shuttle of soluble polysulfides between the two electrodes often results in a rapid capacity decay. Herein, a straightforward electrostatic adsorption strategy based on a cross-linked polyimidazolium separator as a snaring shield of polysulfides is reported, which suppresses the undesirable migration of polysulfides to the anode. The porous ionic network (PIN)-modified carbon nanotubes (CNTs) are successfully prepared and coated onto a commercial porous polypropylene membrane in a vacuum-filtration step. The favorable affinity of the imidazolium ring toward polysulfide via the polar interaction and the electrostatic effect of ions mitigates the undesirable shuttle of polysulfides in the electrolyte, improving the Li─S battery in terms of rate performance and cycling life. Compared to the reference PIN-free CNT-coated separator, the PIN/CNT-coated one has an increased initial capacity of 1.3 folds (up to 1394.8 mAh g−1 for PIN/CNT/PP-3) at 0.1 C.
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| 4. |
- Gao, Zhu, et al.
(författare)
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Interfacial Ti-S Bond Modulated S-Scheme MOF/Covalent Triazine Framework Nanosheet Heterojunctions for Photocatalytic C-H Functionalization
- 2023
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Ingår i: Angewandte Chemie International Edition. - 1433-7851 .- 1521-3773. ; 62:27
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Tidskriftsartikel (refereegranskat)abstract
- Constructing photocatalyst systems to functionalize the inert C−H bonds has attracted extensive research interest. However, purposeful modulation of interfacial charge transfer in heterostructures remains a challenge, as it usually suffers from sluggish kinetics. Reported herein is an easy strategy to construct the heteroatom-induced interface for developing the titanium-organic frameworks (MOF-902) @ thiophene-based covalent triazine frameworks (CTF-Th) nanosheets S-scheme heterojunctions with controllable oxygen vacancies (OVs). Specifically, Ti atoms were first anchored onto the heteroatom site of CTF-Th nanosheets, and then grown into MOF-902 via an interfacial Ti−S linkage, generating OVs. Using in situ X-ray photoelectron spectroscopy (XPS), extended X-ray absorption fine structure (EXAFS) spectroscopy and density functional theory (DFT) calculations, the enhanced interfacial charge separation and transfer induced by moderate OVs in the pre-designed S-scheme nanosheets was validated. The heterostructures exhibited an improved efficiency in photocatalytic C3-acylation of indoles under mild conditions with a yield 8.2 times larger than pristine CTF-Th or MOF-902 and enabled an extended scope of substrates (15 examples). This performance is superior to state-of-the-art photocatalyst and can be retained, without significant loss, after 12 consecutive cycles.
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| 5. |
- Héraly, Frédéric, et al.
(författare)
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Cationic cellulose Nanofibrils-based electro-actuators : The effects of counteranion and electrolyte
- 2023
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Ingår i: Sensors and Actuators Reports. - : Elsevier BV. - 2666-0539. ; 5
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Tidskriftsartikel (refereegranskat)abstract
- 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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| 6. |
- Khorsand Kheirabad, Atefeh, 1991-
(författare)
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Functional hybrid and composite porous membranes derived from imidazolium-type poly(ionic liquid)
- 2023
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Poly(ionic liquid)s (PIL)s, as a subclass of polyelectrolytes, are composed of polymeric backbones with ionic liquid (IL)-based species in each repeating unit. Recent studies have deepened the understanding of the PIL concept in terms of characteristics, functions and applications in comparison to classical ILs and traditional polyelectrolytes. During the past two decades, PILs have developed themselves into an interdisciplinary subject among various research areas such as polymer science, materials science, catalysis, separation and sensing. Currently, the chemistry and applications of conventional polyelectrolytes are being expanded forward by the PIL concept. This PhD thesis deals with PIL-based porous hybrid and composite membranes. It is motivated by the growing demand on functional porous polymer membranes, in particularly, porous polyelectrolyte membranes in both industry and academia. By applying PILs as building blocks in membranes, the as-prepared porous PIL membranes combine certain desirable properties of ILs and common polymers with a wider potential to satisfy this demand. As a step further, the incorporation of functional guest substances on a molecular or nanoscale can enable new functionalities of porous membranes and broaden their application scope. The aim of this thesis is to develop synthetic approaches to fabricate porous PIL-based membranes based on hybridization and composition of a cationic PIL and a guest substance, and explore their diverse functions. Herein, fabrication methods based on two mechanisms were proposed and investigated. First, electrostatic complexation between a cationic hydrophobic PIL and a weak poly-/multi-acid. Second, ice-assisted phase separation of a hydrophobic PIL in water when in contact with a multi-acid compound as an ionic crosslinker. In following, task-specific functions were built up in porous PIL membranes via addition of specific metal-containing substances. This thesis content is inherently interdisciplinary, as it combines polymer chemistry and processing, membrane fabrication and materials science to secure its success in implementation, and this thesis advances the design and application scope of porous polyelectrolyte membranes.
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| 7. |
- Khorsand Kheirabad, Atefeh, 1991-, et al.
(författare)
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Ice-Assisted Porous Poly(ionic liquid)/MXene Composite Membranes for Solar Steam Generation
- 2023
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Ingår i: ACS Applied Materials and Interfaces. - 1944-8244 .- 1944-8252. ; 15:48, s. 56347-56355
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Tidskriftsartikel (refereegranskat)abstract
- Controlled synthesis of polymer-based porous membranes via innovative methods is of considerable interest, yet it remains a challenge. Herein, we established a general approach to fabricate porous polyelectrolyte composite membranes (PPCMs) from poly-(ionic liquid) (PIL) and MXene via an ice-assisted method. This process enabled the formation of a uniformly distributed macroporous structure within the membrane. The unique characteristics of the as-produced composite membranes display significant light-to-heat conversion and excellent performance for solar-driven water vapor generation. This facile synthetic strategy breaks new ground for developing composite porous membranes as high-performance solar steam generators for clean water production.
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| 8. |
- Khorsand Kheirabad, Atefeh, 1991-, et al.
(författare)
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MXene/poly(ionic liquid) porous composite membranes for systematized solar-driven interfacial steam generation
- 2023
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Ingår i: 2D Materials. - : IOP Publishing. - 2053-1583. ; 10:2
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Tidskriftsartikel (refereegranskat)abstract
- Herein, we established a synthetic route towards MXene/poly(ionic liquid) (PIL) composite porous membranes as a new platform of solar-thermal conversion materials. These membranes were made by a base-triggered ionic crosslinking process between a cationic PIL and a weak polyacid in solution in the presence of dispersed MXene nanosheets. A three-dimensionally interconnected porous architecture was formed with MXene nanosheets uniformly distributed within it. The unique characteristics of the as-produced composite membranes displays significant light-to-heat conversion and excellent performance for solar-driven water vapor generation. This facile synthetic strategy opens a new avenue for developing composite porous membranes as solar absorbers for the solar-driven water production from natural resources.
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| 9. |
- Lan, Meng, et al.
(författare)
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Highly redispersible CNT dough for better processiblity
- 2023
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Ingår i: Journal of Materials Science & Technology. - : Elsevier BV. - 1005-0302. ; 152, s. 65-74
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Tidskriftsartikel (refereegranskat)abstract
- Carbon nanotubes (CNTs) have received considerable attention for their excellent thermal and electrical conductivity as well as scalable production. However, CNT dispersions are prone to settling and have a short shelf time, especially under high concentration, which significantly hinders their further processing and increases transportation costs. Here, we report a highly concentrated CNT dough enabled by ionic liquid crystal (ILC) as auxiliaries. Benefiting from the temperature-controlled physical transformation of the ILC, the CNTs of the powder state are successfully transferred to highly processable dough with excellent electrical conductivity, flame retardancy, and outstanding redispersibility even after 180 days of storage. In particular, the CNT dough exhibits excellent self-healing properties and good reshapable capability. Various bulk form CNT derived from the ILC armored CNT dough are realized by facile processing technique. Hybrid nanocomposite papers with ANF nanofiber exhibited excellent photothermal conversion and Joule heating properties. The redispersible CNT doughs presented here promise to revolutionize traditional CNT powder and dispersions as the primary raw material for building CNT-based architectures and facilitate the large-scale application of CNTs.
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| 10. |
- Li, Xinghao, et al.
(författare)
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Porous organic polycarbene nanotrap for efficient and selective gold stripping from electronic waste
- 2023
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Ingår i: Nature Communications. - : Springer Science and Business Media LLC. - 2041-1723. ; 14
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Tidskriftsartikel (refereegranskat)abstract
- The role of N-heterocyclic carbene, a well-known reactive site, in chemical catalysis has long been studied. However, its unique binding and electron-donating properties have barely been explored in other research areas, such as metal capture. Herein, we report the design and preparation of a poly(ionic liquid)-derived porous organic polycarbene adsorbent with superior gold-capturing capability. With carbene sites in the porous network as the “nanotrap”, it exhibits an ultrahigh gold recovery capacity of 2.09 g/g. In-depth exploration of a complex metal ion environment in an electronic waste-extraction solution indicates that the polycarbene adsorbent possesses a significant gold recovery efficiency of 99.8%. X-ray photoelectron spectroscopy along with nuclear magnetic resonance spectroscopy reveals that the high performance of the polycarbene adsorbent results from the formation of robust metal-carbene bonds plus the ability to reduce nearby gold ions into nanoparticles. Density functional theory calculations indicate that energetically favourable multinuclear Au binding enhances adsorption as clusters. Life cycle assessment and cost analysis indicate that the synthesis of polycarbene adsorbents has potential for application in industrial-scale productions. These results reveal the potential to apply carbene chemistry to materials science and highlight porous organic polycarbene as a promising new material for precious metal recovery.
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