Injection Compression Molding And Performances Of Microstructured Or Micro-/nanostructured Surfaces With Inverted Pyramid

The micro-/nanostructures on polymer surfaces endow the surfaces with special optical properties and wettabilities.Injection compression molding is an industrial technology with high efficiency and high precision for preparing micro/nanostructured polymer surface.In this dissertation,microstructured,nanostructured and hierarchically structured Be Cu alloy mold are prepared.Microstructured polystyrene(PS)surface with inverted pyramid and three kinds of structured polypropylene(PP)surfaces are molded by injection compression molding technology.The antireflective,droplet impact robustness and anti-icing property of micro-/nanostructured surfaces are investigated.Ordered pyramid microstructure array is prepared on the surface of mold insert by precision milling and the corresponding inverted pyramid microstructure is replicated on the surface of PS accurately by injection compression molding.Compared with flat PS counterpart,inverted pyramid microstructure can decrease reflectance and increase transmittance.When microstructured PS sample with inverted pyramid is used as a encapsulation layer of solar cell,short-circuit current density and power conversion efficiency are increased under vertical incidence and the enhancement is more obviously as the incident angle increases.Through precision milling,chemical deposition and the combination of them,three kinds of structured mold inserts are prepared.Microstructured PP surface with inverted pyramid,nanostructured PP surface with nanohair and hierarchically structured PP surface with inverted pyramid are molded by injection compression molding.The latter two surfaces exhibit superhydrophobic,low-adhesion and self-cleaning properties.Water droplet can only rebound off the first PP surface when We number is lower than 20.42.The water droplet can rebound off the latter two PP surfaces even at higher We numbers.As the We number increases(20.42?183.75),the contact times of water droplet are not changed and the spreading factors increase.Compared with flat PP surface,the freezing time of water droplet on hierarchically structured PP surface with inverted pyramid is extended and the ice adhesion strength isobviously reduced.The impacting droplet partly rebound off the low temperature(-10? and-20?)nanostructured PP surface with nanohair,whereas the impacting droplet completely rebound off hierarchically structured PP surface with inverted pyramid at the two temperatures.The maximum spreading factor and the maximum stretching factor of water droplet on low temperature hierarchically structured PP surface with inverted pyramid decrease as the inclination of surface increases,while the sliding distance increases.