The Fabrication Of Nanostructure Arrays Of Hydrogelator And Light Emitting Polymers With Improved Performance

As a typical class of the soft condensed matter,polymers have many advantages such as low mass,low cost,flexible,self-organization.The fabrication of nanostructures with the molecular chains and crystalline alignment determines its property and application,which becomes one of the most important research fields in soft condensed matter physics.In our study,we chose the PEG-based polyurethane-urea supramolecular hydrogelator(PUU4K-12),the light emitting polymers poly(9,9-dioctylfluorene)(PFO)and Poly(9,9-di-n-octylfluorene-alt-benzothiadiazole)(F8BT)as the study objects.The nanoimprint lithography was used to fabricate the nanostructures to study the internal relationship between ordered structures(fold,lamellar crystals and molecular chains)of the polymers under naoncofinement and the performance.Additionaly the nanostructures with the alginement of the molecular chains and crystalline were used to fabricate the polymer lasers,and study the effect of the internal structures on the performance of the distributed feedback polymer(DFB)lasers.(1)The nanostructures of the PUU4K-12 were fabricated by the nanoimprint lithography under different temperature,and we studied the relationship between the swelling behaviors and orientation of lamellar crystals.When the nanostructures were fabricated at 70 ?C in which the hydrogen bonded network was not destroyed,the ordered folding structures formed by combinig the surface instability and confined effect.Additionly,the direction,amplitude and wavelength of the ordered folding structres can be controlled by the feature size of the nanostripes such as height and aspection ratio.When the nanostructures were fabricated at 120 ?C in which the hydrogen bonded network was destroyed,we systemically studied the rules of lamellar crystalline orientation under the confinement.Additionally,the anisotropic swelling behaviors can be found in the nanostripes with lamellar crystalline orientation.(2)The F8 BT nanostripes of the light emitting polymers were fabricated by the nanoimprint lithography.The main chains in F8 BT units was oriented along the long axis of the nanostripes,and the crystallinity and orientation degree of the main chains decreased with the increasing confinement size while the torsional angle between F8 and BT units increased with the increasing confinement size.We studied the relationship between the performance of the polymer laser(threshold,slope efficiency and polarization ratio)pumed by the continuous-wave semiconductor lasers and crystallinity,orientation degree and the torsional angle between F8 and BT units.(3)The PFO nanostripes of the light emitting polymers were fabricated by the thermal nanoimprint and slove-assistant room temperature nanoimprint lithography,and the systematic analysis the rules of the alignment of conformation and molecular chains in nanostripes.The ultra-low threshold and linear polarization pure bule lasers was achived by the the continuous-wave semiconductor lasers pumped.According to the study about the fabrication of nanostructures with alignment of the molecular chains and crystalline,we develop a new method to control the different units(fold,lamellar crystals and molecular chains)preferential orientation under confinement,and also gives new insight and guidance for the understanding the effect of the internal preferential orientation on the performance of the devices.