Cold-Resistant Rubbers Based on Flexible Polymer Chains

Comprehensive Summary,As one of the three types of polymeric materials,rubber has played an irreplaceable role in various fields such as industrial production,aerospace,military,and national defense.Improving the cold resistance of rubbers and extending their service temperature range have always been one of the main focuses in rubber research.However,there have been few detailed public reports or literatures on the progress or summary of cold-resistant rubbers,creating an invisible barrier for new researchers wishing to enter this field of research.Therefore,starting from the basis of polymer physics,this review introduces the research difficulties in this field and systematically summarizes the research progress in constructing cold-resistant rubbers based on three different types of flexible polymer chains in recent years.In addition,several important properties of cold-resistant rubbers including mechanical performance,oil resistance,and self-healing ability are also discussed along with the summary of recent progresses.Finally,the future challenges and prospects of cold-resistant rubbers are discussed.

Double safety guarantees:Food-grade photothermal complex with a pH-triggered NIR absorption from zero to one

Photothermal therapy has aroused great attention and showed promising potential in minimally invasive tumor ablation,but the clinical translation is still stifled by the concerns of unwanted injury to normal tissues.The safety concerns might be completely solved only when the two security obstacles of“material-toxicity”and“photo-toxicity”were overcome simultaneously.Herein,a completely non-toxic food-grade photothermal transduction agent(PTA)with double safety guarantees was invented,which shows an absolute transformation of the photothermal effect from“0”to“1”after being triggered by an acidic tumor microenvironment.Inspired by the classical starch-iodine test,a preprogrammed[starch-KI-KIO3]complex was prepared in large quantities through a modified wet-milling procedure.It's demonstrated that a macroscopic consecutive reaction could be triggered by low pH to produce the starch-iodine complex which can generate lethal temperature under the near-infrared light irradiation.Meanwhile,the PTA shows excellent biocompatibility with no“material-toxicity”owing to the raw materials drawn from our daily food.Animal experiments reveal that the tumor microenvironment can activate the switch of photothermal effect from“0”to“1”successfully,which is thus responsible for the discriminative photo-damage to the tumor region while no“photo-toxicity”to normal tissue.The good treatment efficacy confirms the feasibility of such photothermal transduction agents with double safety guarantees in clinical applications.

Photothermal Polymers in Near Infrared Window

Near infrared(NIR)light occupies a significant proportion in solar energy,and it also exhibits high penetration depth in biological tissue owing to its low absorption by pigments and water.Hence,the effective utilization of NIR light is a matter of great significance for energy and biomedical applications.However,the low energy of NIR photons routinely fails to initiate effective photochemical reactions or photoelectric conversion.As an attractive alternative to exciton separation,photothermal conversion ranks as the most efficient approach to use NIR light in the pathways of non-irradiative emission.Based on our efforts in the investigation of photothermal materials and their related applications,this article highlights the factors of light harvesting and photothermal materials in regard to their benefits in improving light use efficiency particularly in NIR window.Several thermally dependent applications which are established on photothermal conversion are exemplified,such as NIR-triggered polymer annealing,control of catalytic reactions,and NIR light detection.

Supramolecular Polymer Emulsifiers for One-step Complex Emulsions

Complex emulsions,such as double emulsions and high-internal-phase emulsions,have shown great applications in the fields of drug delivery,sensing,catalysis,oil-water separation and self-healing materials.Their controllable preparation is at the forefront of interface and material science.Surfactants and polymers have been widely used as emulsifiers for building complex emulsions.Yet some inherent disadvantages exist including multi-step emulsifications and low production efficiency.Alternatively,supramolecular polymer emulsifier for complex emulsions via one-step emulsification is rising as a new strategy due to the ease of preparation.In this feature article,we review our recent progresses in using supramolecular polymer emulsifiers for the preparation of complex emulsions.Double emulsions and high-internal-phase emulsions are successfully prepared via one-step emulsification with the help of different supramolecular interactions including electrostatic,hydrogen bond,coordination interaction and dynamic covalent bond,which will be particularly emphasized in detail.In the end,a comprehensive prospect is given for the future development of this field.This article is expected to provide new inspirations for preparing complex emulsions via supramolecular routes.

Self-healing Ionic Liquid-based Electronics and Beyond

Owing to the advantages of non-volatility,outstanding fluidity and easy recyclability,ionic liquid-based electronics,such as thermometer,strain sensors and thermoelectric converters,have been growing as attractive alternatives to traditionally solid electronics.The fluidic character endows the ionic liquid-based circuit with self-healing ability,satisfying the needs of longer lifetime and less waste generation for electronics,while at the same time brings the risk of leakage.Avoiding the leakage without sacrifice of self-healing ability is one of the major challenges for constructing ionic liquid-based electronic devices.In this feature article,we summarize our recent progresses in developing two types of self-healing electrical devices based on ionic liquids with little risk of leakage.One type involves the encapsulation of ionic liquids in self-healing polymers,and the other type uses ionic polymers or free-standing ionic liquids which are successfully formulated as intrinsically conductive,self-healing,and recyclable electronic devices without additional encapsulation.In the end,a comprehensive outlook is prospected for the future development of ionic liquid-based self-healing electronics,which is expected to spur more innovative work in this field.

Second Near-Infrared Photothermal Therapy with Superior Penetrability through Skin Tissues

Photothermal therapy(PTT)triggered by second near-infrared(NIR-II)light(1000–1400 nm)has shown great potential in tumor ablation because of its good tissue penetrability.However,NIR-II PTT still cannot treat tumors underneath skin because of the light scattering effect of skin components.This research aims to promote the NIR-II penetrability of skin tissue by weakening the light scattering effect from the refractive index inhomogeneity among skin constituents.