Preparation And Characterization Of Regenerated Silk Composite For Thermal Regulation

The reversible phase transition of substance from solid to liquid or vice verse has been widely used to regulate the temperature of surrounding environment,and the substance is commonly called phase change materials(PCM).As a temperature-stable microenvironment can be maintained by the absorption,storage,distribution and release of thermal energy via PCM when the ambient temperature changes,this technique plays an important role in the field of building energy saving and intelligent textiles.Although silk is one of the earliest natural fibers used by human,it is particularly attractive nowadays in the biomedical field due to good biocompatibility and biodegradability.In addition to the traditional textiles,silk has been developed recently as biomaterials which includes drug controlled-release carrier,wound dressing and tissue engineering scaffolds accordingly.In the present study described here,silk fibroin solution was firstly obtained from silk through the process of degumming,dissolving,dialysis and concentration.Then the regenerated silk composites for thermal regulation were developed from silk fibroin solution and n-octadecane,one of the most important substances of PCM.Various of techniques were used to get the regenerated silk based composites in the form of microcapsules,fiber,film and hydrogel,and effects of the preparation parameters on the microstructures and thermal properties of composites were systematically investigated.The PCM microcapsules with regenerated silk wall were firstly synthesized and the microcapsules present a spherical shape with a uniform size distribution,high thermo-regulation capability and excellent thermal reliability.The microcapsules were incorporated into the polyurethane sponge by the deposition method with the aid of ultrasonic agitation,and a kind of functional dressing with temperature regulation and good cell compatibility was accordingly obtained.The composite fibers consisting PCM and regenerated silk were successfully fabricated by the emulsion elecrospinning technique.The composite fibers display cylindrical shape with smooth surface and an average diameter of about 1.0 ?m.Furthermore,the composite fibers exhibit high temperature regulating capacity and excellent cell compatibility,which are great promising candidates in the application as intelligent textiles and functional wound dressings.The fabrication of regenerated silk film with bifunction of temperature monitoring and thermal regulation was developed by the incorporation of thermochromic microcapsules into silk fibroin via the casting method.The color of composite film changes reversibly with the ambient temperature and the composite film possesses the capability to maintain a surrounding with constant temperature.In addition,the composite film shows good biocompatibility and strong mechanical property.Eventually,the PCM incorporated silk hydrogel was developed by a simple method,and the composite hydrogel exhibits high water absorption capability and good temperature regulation capacity.Therefore the composite hydrogel can be used as a packaging material for the storage and transport of heat sensitive and water sensitive substances.