Raspberry-Shaped Thermochromic Energy Storage Nanocapsule with Tunable Sunlight Absorption Based on Color Change for Temperature Regulation

Multi-Stimuli Dually-Responsive Intelligent Woven Structures with Local Programmability for Biomimetic Applications

This work focuses on multi-stimuli-responsive materials with distinctive abilities, that is, color-changing and shape-memory. Using metallic composite yarns and polymeric/thermochromic microcapsule composite fibers, processed via a melt-spinning technique, an electrothermally multi-responsive fabric is woven. The resulting smart-fabric transfers from a predefined structure to an original shape while changing color upon heating or applying an electric field, making it appealing for advanced applications. The shape-memory and color-changing features of the fabric can be controlled by rationally controlling the micro-scale design of the individual fibers in the structure. Thus, the fibers' microstructural features are optimized to achieve excellent color-changing behavior along with shape fixity and recovery ratios of 99.95% and 79.2%, respectively. More importantly, the fabric's dual-response by electric field can be achieved by a low voltage of 5 V, which is smaller than the previously reported values. Above and beyond, the fabric is able to be meticulously activated by selectively applying a controlled voltage to any part of the fabric. The precise local responsiveness can be bestowed upon the fabric by readily controlling its macro-scale design. A biomimetic dragonfly with the shape-memory and color-changing dual-response ability is successfully fabricated, broadening the design and fabrication horizon of groundbreaking smart materials with multiple functions.

Quasi-Homogeneous and Hierarchical Electronic Textiles with Porosity-Hydrophilicity Dual-Gradient for Unidirectional Sweat Transport, Electrophysiological Monitoring, and Body-Temperature Visualization

On-skin electronics based on impermeable elastomers and stacking structures often suffer from inferior sweat-repelling capabilities and severe mechanical mismatch between sub-layers employed, which significantly impedes their lengthy wearing comfort and functionality. Herein, inspired by the transpiration system of vascular plants and the water diode phenomenon, a hierarchical nonwoven electronic textile (E-textile) with multi-branching microfibers and robust interlayer adhesion is rationally developed. The layer-by-layer electro-airflow spinning method and selective oxygen plasma treatment are utilized to yield a porosity-hydrophilicity dual-gradient. The resulting E-textile shows unidirectional, nonreversible, and anti-gravity water transporting performance even upon large-scale stretching (250%), excellent mechanical matching between sub-layers, as well as a reversible color-switching ability to visualize body temperature. More importantly, the conducting and skin-conformal E-textile demonstrates accurate and stable detecting capability for biomechanical and bioelectrical signals when applied as an on-skin bioelectrode, including different human activities, electrocardiography, electromyogram, and electrodermal activity signals. Further, the E-textile can be efficiently implemented in human-machine interfaces to build a gesture-controlled dustbin and a smart acousto-optic alarm. Hence, this hierarchically-designed E-textile with integrated functionalities offers a practical and innovative method for designing comfortable and daily applicable on-skin electronics.

Synergistically Enhancing the Therapeutic Effect on Cancer, via Asymmetric Bioinspired Materials

The undesirable side effects of conventional chemotherapy are one of the major problems associated with cancer treatment. Recently, with the development of novel nanomaterials, tumor-targeted therapies have been invented in order to achieve more specific cancer treatment with reduced unfavorable side effects of chemotherapic agents on human cells. However, the clinical application of nanomedicines has some shortages, such as the reduced ability to cross biological barriers and undesirable side effects in normal cells. In this order, bioinspired materials are developed to minimize the related side effects due to their excellent biocompatibility and higher accumulation therapies. As bioinspired and biomimetic materials are mainly composed of a nanometric functional agent and a biologic component, they can possess both the physicochemical properties of nanomaterials and the advantages of biologic agents, such as prolonged circulation time, enhanced biocompatibility, immune modulation, and specific targeting for cancerous cells. Among the nanomaterials, asymmetric nanomaterials have gained attention as they provide a larger surface area with more active functional sites compared to symmetric nanomaterials. Additionally, the asymmetric nanomaterials are able to function as two or more distinct components due to their asymmetric structure. The mentioned properties result in unique physiochemical properties of asymmetric nanomaterials, which makes them desirable materials for anti-cancer drug delivery systems or cancer bio-imaging systems. In this review, we discuss the use of bioinspired and biomimetic materials in the treatment of cancer, with a special focus on asymmetric nanoparticle anti-cancer agents.

Concomitant Thermochromic and Phase-Change Effect in a Switchable Spin Crossover Material for Efficient Passive Control of Day and Night Temperature Fluctuations

The increasing environmental protection demand has prompted the development of passive thermal regulation systems that reduce temperature fluctuations in buildings. Here, it is demonstrated that the heat generated by the sun can trigger a spin crossover (SCO) in a molecule-base material, resulting in a concomitant color variation (from pink to white) and a phase transition. This leads to a cooling effect with respect to other thermochromic materials. In addition, when the material is cooled, a dampening of the temperature decrease is produced. Therefore, these materials can potentially be implemented for passive temperature control in buildings. Furthermore, SCO materials are remarkably stable upon cycling and highly versatile, which allows for the design of compounds with properties tailored for the desired climatic conditions and comfortable temperature.

Recent Progress on Asymmetric Carbon- and Silica-Based Nanomaterials: From Synthetic Strategies to Their Applications

HIGHLIGHTS

The synthetic strategies and fundamental mechanisms of various asymmetric carbon- and silica-based nanomaterials were systematically summarized. The advantages of asymmetric structure on their related applications were clarified by some representative applications of asymmetric carbon- and silica-based nanomaterials. The future development prospects and challenges of asymmetric carbon- and silica-based nanomaterials were proposed.

ABSTRACT

Carbon- and silica-based nanomaterials possess a set of merits including large surface area, good structural stability, diversified morphology, adjustable structure, and biocompatibility. These outstanding features make them widely applied in different fields. However, limited by the surface free energy effect, the current studies mainly focus on the symmetric structures, such as nanospheres, nanoflowers, nanowires, nanosheets, and core–shell structured composites. By comparison, the asymmetric structure with ingenious adjustability not only exhibits a larger effective surface area accompanied with more active sites, but also enables each component to work independently or corporately to harness their own merits, thus showing the unusual performances in some specific applications. The current review mainly focuses on the recent progress of design principles and synthesis methods of asymmetric carbon- and silica-based nanomaterials, and their applications in energy storage, catalysis, and biomedicine. Particularly, we provide some deep insights into their unique advantages in related fields from the perspective of materials’ structure–performance relationship. Furthermore, the challenges and development prospects on the synthesis and applications of asymmetric carbon- and silica-based nanomaterials are also presented and highlighted. [Image: see text]

Active Encapsulation in Biocompatible Nanocapsules

Co-precipitation is generally refers to the co-precipitation of two solids and is widely used to prepare active-loaded nanoparticles. Here, it is demonstrated that liquid and solid can precipitate simultaneously to produce hierarchical core-shell nanocapsules that encapsulate an oil core in a polymer shell. During the co-precipitation process, the polymer preferentially deposits at the oil/water interface, wetting both the oil and water phases; the behavior is determined by the spreading coefficients and driven by the energy minimization. The technique is applicable to directly encapsulate various oil actives and avoid the use of toxic solvent or surfactant during the preparation process. The obtained core-shell nanocapsules harness the advantage of biocompatibility, precise control over the shell thickness, high loading capacity, high encapsulation efficiency, good dispersity in water, and improved stability against oxidation. The applications of the nanocapsules as delivery vehicles are demonstrated by the excellent performances of natural colorant and anti-cancer drug-loaded nanocapsules. The core-shell nanocapsules with a controlled hierarchical structure are, therefore, ideal carriers for practical applications in food, cosmetics, and drug delivery.