Investigation Of Entropy Induced, Multi-Responsive Self-Storage Functional Materials With Microscale Liquid Phase

Responsive materials is a kind of functional materials which can response to external stimulus. It is also named as stimuli-responsive materials or smart materials. If external conditions, like light, temperature, pH, ionic strength, electric or magnetic field, have changed, many properties of itself such as phase, shape surface energy, reacting rate, penetrating rate, or recognition features will also be transformed. It is truth that the field of responsive materials has made a huge progress in recent years. Existed responsive materials in polymer area mainly include pH response, thermal response, light response, glucose response, and field response materials.The applications of these materials are extremely wide according to large number of reported papers. Thus, responsive materials are highly potential to varied fields such as controlled drug release, biology engineering and catalyst. Hydrogels are widely discussed in recent works and become a typical model of responsive materials. Generally, it has an obvious volume change when response to outside conditions. On one hand, taking fully advantage of this feature can satisfy certain needs, such as fabricating a kind of responsive lens like human eyes, or a drug release system. On the other, it may cause a problem of denpendence of external solvent, for instance, a hydrogel can only recover its original shape in water environment. Moreover, this behavior will more or less affect the structural stability of responsive materials in solid devices. Therefore, this work may fill up a blank area of responsive materials on its response mechanism. It can not only resolve the dependence of external solvent, but also its application on solid devices.The core reason of the distorted shape of responsive polymer materials is due to the serious stretch of polymer chains which lead to the collapse of its appearance. So the problem may be solved if serious stretch of polymer chains is restricted and phase separation is controlled. This thesis was begun with the Flory-Huggins theory, from which we can deduce a general factor of controlling the entropic effect in polymer blends. For typical polymer blends, entropic always favors mixing, so from this point, we successful develop a series of non-distorted responsive materials. Scanning electronic microscope images present a structure of a large number of micro pores, which indicates its phase separation obeys a kind of self-storage behavior. Plenty of tiny liquid droplets are stored in materials rather than expelling out, as we called “self-storage” responsive materials.Due to self-storage materials are independent to outside solvent. It will probably be applied in some solid devices, like solid electrolyte, supercapacitor, etc. So in this work, we also introduce certain amount of ionic liquid in polymers to improve its conductivity. The electrochemical impedance spectrum suggest that the phase behavior has a huge impact on its impedance property, based on which we may able to develop a kind of sensitive solid electrolyte.As a kind of responsive materials, it is also important to develop certain routes to control its response feature in different circumstances. The work also has investigated the nano effect in self-storage materials via dispersing nano silica in isopropyl alcohol. The responsive feature can partly controlled by the amount of nano silica and the polymerizable ligands on its surface.At last, this thesis conduct other extended research on self-storage materials. Due to the polymer PMMA was flexible after small liquid molecules diffused in. It can be taken advange to fabricate a kind of polymer memoriable materials. Furthermore, we found a strong self-healing ability in an ionic liquid doped sample. All these attractive features will probably act as important roles for future muti-functional materials.