Heat-controlled micropillar array device for microsystems technology.

A new temperature-controlled smart soft material micropillar array has been fabricated via in situ integration of the liquid-crystalline elastomer-based component into the hybrid microdevice. Such design allows for developing pushing elements with fast lifetime values of ca. 5 s, and opens huge opportunities for the use of hybrid smart microdevices with total control on the actuation time/response, repeatability, stability and energy saving.

Localised actuation in composites containing carbon nanotubes and liquid crystalline elastomers.

A liquid crystalline elastomer-carbon nanotube (LCE-CNT) composite displays a reversible shape change property in response to light. The development of some systems such as tactile devices requires localised actuation of this material. A method is reported that combines mechanical stretching and thermal crosslinking of an LCE-CNT for creating sufficiently well-aligned liquid crystal units to produce localised actuation. The method demonstrates that it is feasible to optically drive a LCE-CNT film within a localised area, since only the walls of the stretched parts of the film contain aligned LC domains.

Tactile acuity charts: a reliable measure of spatial acuity.

For assessing tactile spatial resolution it has recently been recommended to use tactile acuity charts which follow the design principles of the Snellen letter charts for visual acuity and involve active touch. However, it is currently unknown whether acuity thresholds obtained with this newly developed psychophysical procedure are in accordance with established measures of tactile acuity that involve passive contact with fixed duration and control of contact force. Here we directly compared tactile acuity thresholds obtained with the acuity charts to traditional two-point and grating orientation thresholds in a group of young healthy adults. For this purpose, two types of charts, using either Braille-like dot patterns or embossed Landolt rings with different orientations, were adapted from previous studies. Measurements with the two types of charts were equivalent, but generally more reliable with the dot pattern chart. A comparison with the two-point and grating orientation task data showed that the test-retest reliability of the acuity chart measurements after one week was superior to that of the passive methods. Individual thresholds obtained with the acuity charts agreed reasonably with the grating orientation threshold, but less so with the two-point threshold that yielded relatively distinct acuity estimates compared to the other methods. This potentially considerable amount of mismatch between different measures of tactile acuity suggests that tactile spatial resolution is a complex entity that should ideally be measured with different methods in parallel. The simple test procedure and high reliability of the acuity charts makes them a promising complement and alternative to the traditional two-point and grating orientation thresholds.