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In this paper, we present a simple and costeffective replication method of high-aspect-ratio polymer nanopillar array as a biomimetic gecko's foot hair prototype. A UV nano embossing process was applied for the replication of polymer nanopillar arrays. Highly ordered straight nanoporous AAO (anodic aluminum oxide) templates were utilized as reusable master molds. Densely arranged high-aspect-ratio nanopillar arrays have been successfully fabricated by means of the UV nano embossing process with the AAO mold. Pull-off force measurements were carried out to characterize the adhesive force of the replicated nanopillar arrays on the polymer substrates based on the force-distance curves obtained from the atomic force microscope (AFM) with a modified AFM cantilever. The force measurement results showed that the larger diameter and the taller height of the nanopillars result in the larger adhesive force.

This study examined the effect of three compatibilizers, namely, a hybrid compatibilizer composed of polypropylene‐maleic anhydride (PP‐g‐MAH) and polyethylene‐glycidyl methacrylate (PE‐g‐GMA), a single compatibilizer composed of PP‐g‐MAH, and a single compatibilizer composed of PE‐g‐GMA, on the mechanical, morphological, and rheological properties of a ternary blend of polypropylene (PP), poly(lactic acid; PLA), and a toughening modifier. The results of tensile strength, flexural strength, and impact strength tests for the ternary blends before and after hydrolysis, revealed that the ternary blend with a hybrid compatibilizer content of 3 phr exhibited better material properties than the blend containing a single compatibilizer. In the weighted relaxation spectra of the ternary blend using the Palierne emulsion model, the ternary blend containing the hybrid compatibilizer, exhibited only one relaxation spectrum peak at ∼ 0.16 s. This result suggests that the ternary blend with the hybrid compatibilizer exhibits uncharacteristic morphological properties, that is, a single‐phase microstructure. The above results suggest that the hybrid mixture is an effective compatibilizer for the ternary blend of PP, PLA, and a toughening modifier. POLYM. COMPOS., 2012. © 2012 Society of Plastics Engineers

In recent years, UV nano embossing (or imprinting) process has been widely used for mass replication of nano structures. Most of the UV embossing machines use a UV transparent mold insert (e.g. quartz or glass). However, when a master of nano structures of interest could be realized only in a UV non-transparent mold material, it would be desirable to have a UV embossing machine which could be operated with such a UV non-transparent mold insert. In this regard, we have designed and manufactured a new UV embossing system in such a way that UV non-transparent (e.g., metal or ceramic) mold inserts can also be used as the master for the mass replication of nano structures. For the new UV embossing system, we fabricate several metal mold inserts: a nickel electroformed mold insert having grating nano structures and two AAO (anodic aluminum oxide) mold inserts having dimple nano structures and highaspect-ratio nanopores. Finally, corresponding nano structures are successfully replicated via the UV nano embossing machine developed in this study.

Bonding is an essential step to form microchannels or microchambers in lab-on-a-chip applications. In this paper, we present a novel plastic thermal bonding technique to seal and form large area microchambers (planar characteristic width and length on the order of 1 mm and characteristic thickness on the order of 10-100 lm) without collapse by introducing a holed pressure equalizing plate (HPEP) that includes holes of the same size and shape as the microchambers. To demonstrate the proposed technique, two types of large area microchambers [(1) 20 · 10 mm and 40 lm thick and (2) 12 · 2.5 mm and 120 lm thick] with microchannels were designed and replicated on plastic substrates by means of hot embossing and injection molding processes with prepared two nickel mold inserts. The replicated large area microchambers as well as the microchannels in the plastic lab-on-a-chip were successfully sealed (i.e., no leakage) and formed without any collapse by the proposed thermal bonding technique with the help of the HPEP.