Fabrication And Application Of PDMS-based Porous Wrinkles

In recent years, because of it’s tremendously amount of applications inbiosensor, optical, micro-transfer field, hierarchical structures which include wrinklemicro-pattern have attracted more and more interest. Currently, there are some mainmethods to fabricate different hierarchical structures. However, it is still a bigchallenge to develop an easy and fast way to fabricate highly complex hierarchicalstructure.In order to fabricate hierarchical structures which contained wrinkle andmicro-holes, we combined wet chemical etching and mechanical pre-stretch exposuremethod. That is to say we use wet chemical etching to get the micro-holes and usemechanical pre-stretch exposure method to fabricate wrinkle pattern. We couldcontrol the hierarchical structures by adjusting the order of two steps and the way ofmechanical pre-stretch exposure. During the preparation, we investigated severalfactors which include the treatment duration with O2plasma and UVO, etching timewith HF, stretching ratio and etching temperature. These factors have seriously impacton wrinkle formation. We also focused on the solidification of the wrinkle pattern bythe second exposure treatment.In addition, we use porous PDMS wrinkles as the stamp for investigation theirapplication in the micro-transfer field. For the sake of controlling the process oftransfer, we systematically investigate the factors including contact time, necessity ofthe substrate treatment, transfer atmosphere and loaded weight, which have an effecton the transferred microstructure. The results show that our PDMS stamp with thehierarchically porous wrinkles has greatly enhanced the ink reserve and transferefficiency.