Preparation and application of carbon nanotubes flexible sensors

Based on the good extensibility and conductivity,the flexible sensors(FSs)have a wide range of applications in the field of the electrochemical energy storage and variable stress sensors,which causes that the preparation of FSs also become a hot spot of research.Among the materials for preparing the FSs,the flexible carbon matrix composites(FCMCs)have become the widely used material since the good performance in the properties of electrochemistry and mechanics,which could be divided into three types:the carbon nanofibers(CNFs),the carbon nanospheres(CNSs)and the carbon nanotubes(CNTs).Compared with CNFs and CNSs,the CNTs wrapped by the polydimethylsiloxane(PDMS)have the advantages of the excellent extensibility and electrochemical stability.Therefore,the CNTs flexible sensor(CFS)could be well used in the field of the FSs.The purpose of this review is summarizing the preparation methods and application fields of CFS and proposing the research direction of CFS in the future.In this paper,two methods for fabricating the CFS have been designed by consulting the methods mentioned in the literature in recent years,and the advantages and disadvantages between the two methods have been explained.The application fields of CFS in recent years are enumerated,and the conclusion that the application fields of CFS are very wide is drawn.At the end of this paper,the review concludes with an overview of key remaining challenges in the application fields of the CFS.

Infrared cooling properties of cordierite

Cordierite(Mg2 Al4 Si5 O18) is known for its good thermal shock resistance and it is widely used to improve thermal shock properties of materials. We found that cordierite has good infrared heat dissipation performance. This performance provides an additional means of heat dissipation to assist in the cooling of the metal surface. Spectroscopic tests show that cordierite reflects sunlight in the visible range and emits infrared in the far infrared range, making it potential candidate as an infrared radiative cooling material for daytime use.

Electrospun flexible sensor

Flexible sensors have received wide attention because of their ability to adapt to a variety of complex environments.Electrospinning technology has significant advantages in the preparation of flexible sensors.This paper summarizes the progress in the preparation of flexible sensors by electrospinning.Sensors that respond to light,stress,and gas are presented separately.Finally,some directions for electrospinning and flexible sensors are discussed.

Preface to the Special Issue on Flexible and Wearable Sensors for Robotics and Health

Flexible and wearable sensors that can acquire signals of pressure,temperature,optical input,chemical environment as well as human body physiological and biological parameters,are of critical importance for robotics and health,in which these sensors are hence in urgent demands.On the fundamental side,there are still substantial challenges on how to design and fabricate materials with biocompatibility,robustness and excellent mechanical flexibility,as well as to achieve sensor devices with high performance,low power consumption and good system integration capability.Meanwhile in practical applications,there are also obstacles on the integration of various kinds of sensors with flexible substrates,signal processing and power supply units.With the fast development of Internet of Things(IoT),smart sensors will as well be interconnected to form sensor networks,providing big data for our future intelligent living.All these would deliver a profound socioeconomic impact to our society.

A non-surgical suturing strategy for rapid cardiac hemostasis

As the central organ of the human body,once the heart is damaged,it will cause devastating damage to the circulation system of the whole body,often leading to rapid death.Currently,the only treatment option to stop bleeding in penetrating cardiac injuries is surgical suturing,which is extremely complex and risky.In addition,it is difficult to implement this kind of treatment in battlefields with poor medical conditions.Therefore,there is an urgent need to develop an effective cardiac hemostasis strategy.In this work,we propose a two-step hemostasis strategy that can effectively stop bleeding for penetrating heart injuries.That is,cardiac hemostatic plug(CHP)is made from the nanocomposite(polylactic acid/gelatin/absorbable hemostatic particles,PLA/GEL/AHP)with high biosafety,excellent hemostatic performance,and degradability which is used to block cardiac bleeding,and then wound surface is sealed by in-situ electrospun medical glue fibers(N-octyl-2-cyanoacrylate,interfacial toughness:221±23 J·m−2),thus completing cardiac hemostasis(porcine heart with 1 cm diameter penetrating wound).The hemostasis process is simple and quick(<2 min).In addition,it is worth mentioning that we have also proposed a new composite method based on solution blow spinning that is suitable for doping various functional particles,and the PLA/GEL/AHP composite nanofiber membrane prepared by this method is also a promising hemostatic material.

Advances in 3D printing of magnetic materials:Fabrication,properties,and their applications

Magnetic materials are of increasing importance for many essential applications due to their unique magnetic properties.However,due to the limited fabrication ability,magnetic materials are restricted by simple geometric shapes.Three-dimensional(3D)printing is a highly versatile technique that can be utilized for constructing magnetic materials.The shape flexibility of magnets unleashes opportunities for magnetic composites with reducing post-manufacturing costs,motivating the review on 3D printing of magnetic materials.This paper focuses on recent achievements of magnetic materials using 3D printing technologies,followed by the characterization of their magnetic properties,which are further enhanced by modification.Interestingly,the corresponding properties depend on the intrinsic nature of starting materials,3D printing processing parameters,and the optimized structural design.More emphasis is placed on the functional applications of 3D-printed magnetic materials in different fields.Lastly,the current challenges and future opportunities are also addressed.

Novel elastico-mechanoluminescence materials CaZnOS:Mn^(2+)and CaZr(PO_(4))_(2):Eu^(2+)

This paper highlights our work on the recent progress in novel elastico-mechanoluminescence(EML)materials CaZnOS:Mn^(2+)and CaZr(PO_(4))_(2):Eu ^(2+),which can simultaneously"feel"(sense)and"see"(image)the applied mechanical stress as an intense and proportional luminescence.CaZnOS:Mn 2þcan sense various types of mechanical stress,including ultrasonic vibration,impact,friction and compression because of the large piezoelectric coefficient.CaZr(PO_(4))_(2):Eu ^(2+)with multiple trap levels shows a broad measurement range for dynamic load.Both of CaZnOS:Mn^(2+)and CaZr(PO_(4))_(2):Eu ^(2+)belong to the defect-controlled type pie-zoelectric phosphors,and their EML mechanisms could be explained using the piezoelectrically induced carrier de-trapping model.