Polyvinylidene fluoride (PVDF) is widely used in the fields of energy storage, sensors, and energy collection due to its excellent dielectric, piezoelectric, and ferroelectric properties. PVDF has a variety of crystalline phases, which correspond to different molecular conformations and physical properties. At present, there are still controversies about which PVDF crystal phases dominate under certain conditions, the corresponding morphological characteristics of each crystal phase, and the influence on the physical properties of PVDF. This article reviewed the structural characteristics of the three main crystal forms (α, β and γ) of PVDF and the current mainstream characterization methods, and analyzed the difficulties and potential ways to accurately establish the "structure-activity" relationship of PVDF polymorphs. The factors affecting the formation of PVDF polymorphs and the transformation rules were also reviewed.
| 科 Family | 属数 Number of genus | 种数 Number of species | 占总种数比例 Percentage of total species (%) | 属 Genus | 种数 Number of species | 占总种数比例 Percentage of total species (%) |
|---|---|---|---|---|---|---|
| 鹅膏菌科Amanitaceae | 2 | 11 | 5.26 | 鹅膏菌属 Amanita | 10 | 4.78 |
| 小菇科 Mycenaceae | 2 | 12 | 5.74 | 丝盖伞属 Inocybe | 5 | 2.39 |
| 多孔菌科 Polyporaceae | 8 | 14 | 6.70 | 蜡蘑属 Laccaria | 5 | 2.39 |
| 红菇科 Russulaceae | 3 | 23 | 11.00 | 小皮伞属 Marasmius | 6 | 2.87 |
| 小菇属 Mycena | 11 | 5.26 | ||||
| 光柄菇属 Pluteus | 5 | 2.39 | ||||
| 红菇属 Russula | 17 | 8.13 | ||||
| 栓菌属 Trametes | 5 | 2.39 |