No abstract

Preparation of sub-micrometer-sized tube dendrites of polyaniline and polypyrrole: Aniline (91 lL, 1 mmol) and various acids (e.g., D-CSA, b-NSA, and 1,5-NDSA) with a molar ratio of 2:1 were dissolved in 20 mL deionized water and stirred magnetically at 0 to 5 C (ice bath). 5 mL of an aqueous solution of (NH 4 ) 2 S 2 O 8 (0.2 mol L ±1 ) was added to the aniline/acid solution in one portion. The resulting solution was stirred for another 2 min to ensure complete mixing. Then the reaction was allowed to proceed without agitation for 24 h at 0 to 5 C. After that, the resulting product was collected by filtration and washed several times with water, methanol, and diethyl ether. Finally it was dried in a dynamic vacuum at room temperature for 24 h. A similar, but slightly modified procedure was used to synthesize the PPy sub-micrometer-sized tube dendrites doped with p-TSA: FeCl 3 was used as the oxidant. Its aqueous solution (7 mL, 1.0 mol L ±1 ) was added dropwise to the pyrrole/p-TSA solution (10 mL, PPy, 0.7 mol L ±1 ; p-TSA, 1.0 mol L ±1 ) very slowly (i.e., one drop per minute). Then the reaction was allowed to proceed for 24 h at 0 to 5 C. In order to mix homogeneously but not to affect the aggregation of PPy sub-micrometer-sized tubes, slow magnetic stirring (e.g. 10 rev min ±1 ) is needed when adding the oxidant.

Phase separation micromolding (PSmicroM) is a versatile microfabrication technique that can be used to structure a very broad range of polymers, including block copolymers and biodegradable and conductive polymers without the need for clean-room facilities. By incorporating a subsequent process step, carbon, ceramic, and metallic microstructures can also be fabricated from a polymeric or hybrid precursor. The replication process is straightforward and cost-effective. It relies on phase separation of a polymer solution while in contact with a structured mold. Intrinsic shrinkage during the phase separation facilitates the release of the replica from the mold, which increases the reliability of the process even at small feature sizes, thin polymer films, or high aspect ratios. Under suitable circumstances perforation of the polymer film can be obtained, resulting in completely open "through" microstructures. Furthermore, porosity can be introduced in a microstructure, which may result in unknown functionalities.

A fast and reliable method is reported for fabricating superhydrophobic surfaces. The method combines microstructure replication with polymer phase inversion and can be applied to a wide variety of polymers. This method provides a surface that contains roughness on two independently controllable levels, i.e., the microstructure level and the level of porosity stemming from the phase inversion. Both levels were optimized separately, resulting in water contact angles up to 167 degrees.

Extended photonic crystal slabs with light‐guiding defects have been created by a combination of laser interference lithography (LIL) and local focused ion beam (FIB) assisted deposition. Large area, highly uniform photonic crystal slabs for visible light are thus made possible. The Figure shows a freestanding Si3N4–air photonic crystal with a light‐guiding defect line running along the center of the slab (total length = 1 mm).