A humidity-responsive bilayer actuator has been developed that consists of an oriented polyamide-6 substrate and a liquid-crystalline polymer coating. The oriented substrate acts as an alignment layer for the liquid crystal. The liquid-crystalline polymer consists of a supramolecular network having hydrogen-bonded entities that, after activation with an alkaline solution, exhibit deformation in response to a change in humidity. The bending behavior of the bilayer actuator was analyzed, showing a large response to a change in the humidity.

A flexible, strain sensor for monitoring uniaxial deformations in oriented polymer films is demonstrated. The sensor consists of a crosslinked cholesteric liquid crystal layer which is spray-coated on a uniaxially oriented polyamide 6 substrate. When no deformation is applied, reflectivity measurements showed a well-defined reflection band. Upon uniaxial extension, the reflection band shifted towards lower wavelengths. A 40 nm shift was recorded for 13% of strain. This wavelength shift is attributed to a decrease in the cholesteric helix's pitch which is induced by the change in thickness of the CLC coating due to Poisson's contraction. As a result the colour of the film changed from orange to green with increasing strain. The optical response was found to follow the mechanical behaviour of the polymer substrate. Cycling loading showed a time dependent optical response of the sensor fitting with the viscoplastic mechanical response of the substrate giving real time information on the deformation.

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A new approach for the production of oriented films and fibers with angular-dependent reflective colors is presented. The process consists of spray coating a solution of cholesteric liquid-crystalline monomers onto a melt-processed and oriented polyamide-6 substrate followed by UV curing. Reflectivity measurements and optical microscopy show that a well-defined liquid-crystalline and planar alignment is obtained. It is further demonstrated that a reflection up to 80% is obtained by coating oriented films on both sides of the oriented substrate with a single-handedness cholesteric liquid-crystal coating. The high reflectivity is attributed to the close to half-wave retardation induced by the anisotropic polymer substrate. Also, polyamide-6 filaments are successfully coated and fibers are obtained with an angular-dependent color in a single dimension along the fiber direction, which originates from the planar cholesteric alignment on a curved surface.

As one member of high performance fibers, aromatic polyimide fibers possess many advantages, such as high strength, high modulus, high and low temperature resistance, and radiation resistance. However, the preparation of the high performance fibers is so difficult that the commercial fibers have not been produced except P84 with good flame retardancy. In this report, a polyimide was synthesized from 3,3Ј,4,4Ј-biphenyltetracarboxylic dianhydride (BPDA) and 4,4Ј-oxydianiline (ODA) and the fibers were prepared from its solution by a dry-jet wet-spinning process. The formation of the as-spun fibers in different coagulation bath composition was discussed. Scanning electron microscope (SEM) was employed to study the morphology of the as-spun fibers. As a result, the remnant solvent existed in the as-spun fibers generated from coagulation bath of alcohol and water. There were many fibrils and microvoids with the dimension of tens of nanometers in the fibers. One could observe the obvious fibrillation and the drawn fibers. The measurement for the mechanical properties of the fibers with a drawing ratio of 5.5 indicated that tensile strength and initial modulus were 2.4 and 114 GPa, respectively.