We describe the use of hard etching methods to create nanodimensional channels and their use as templates for the formation of polymer filament arrays with precise dimensional and orientational control in a single integrated step. The procedure is general as illustrated by the radical, coordination, and photochemical polymerizations that were performed in these nanochannels. The nanochannel templates (20 nm high, 20-200 nm wide, and 100 mum long) were fabricated by the combined use of electron-beam lithography and a sacrificial metal line etching technique. Radical polymerization of acrylates, metal-catalyzed polymerization of norbornene, and photochemical polymerization of 1,4-diiodothiophene were carried out in these nanochannels. The polymers grown follow the dimensions and orientation of the channels, and the polymer filaments can be released without breaking. The approach opens up the possibility of just-in-place manufacturing and processing of patterns and devices from nanostructured polymers using well-established polymer chemistry. 相似文献
We have plotted electropherograms in capillary zone electrophoresis (CZE) as a function of the quantity of electric charge (Q) in order to eliminate the dependency of the analyte peak areas, as well as that of the migration times, upon both the capillary temperature and the applied voltage. The procedure is based on an idea of a migration index (MI) and an adjusted migration index (AMI) which were originally proposed by Lee and Yeung. The value of Q is measured accurately and calculated easily because it is given by a product of the electrophoretic current and the migration times, where the index MI is derived by dividing the value of Q by the effective volume of the capillary. By calculating the CZE peak area from the newly plotted electropherogram, improvement in precision in quantitative analysis is expected. Concerning AMI, careful treatment is required in its application to analyte peaks whose migration time is close to that of the neutral marker. Experimental data and discussions concerning the migration indices are presented. 相似文献
Side-chain engineering has been demonstrated as an effective method for fine-tuning the optical, electrical, and morphological properties of organic semiconductors toward efficient organic solar cells (OSCs). In this work, three isomeric non-fullerene small molecule acceptors (SMAs), named BTP-4F-T2C8, BTP-4F-T2EH and BTP-4F-T3EH, with linear and branched alkyl chains substituted on the α or β positions of thiophene as the side chains, were synthesized and systematically investigated. The results demonstrate that the size and substitution position of alkyl side chains can greatly affect the electronic properties, molecular packing as well as crystallinity of the SMAs. After blending with donor polymer D18-Cl, the prominent device performance of 18.25% was achieved by the BTP-4F-T3EH-based solar cells, which is higher than those of the BTP-4F-T2EH-based (17.41%) and BTP-4F-T2C8-based (15.92%) ones. The enhanced performance of the BTP-4F-T3EH-based devices is attributed to its stronger crystallinity, higher electron mobility, suppressed biomolecular recombination, and the appropriate intermolecular interaction with the donor polymer. This work reveals that the side chain isomerization strategy can be a practical way in tuning the molecular packing and blend morphology for improving the performance of organic solar cells.
