Thermochromic poly[3‐(2‐methyl‐1‐butoxy)‐4‐methylthiophene] has been investigated in the solid state. Some important changes have been observed by UV‐Vis absorption and XRD measurements. Solid‐state NMR spectroscopy, which has the ability to provide information about the structure and dynamics of polymers over a wide range of length scales and time scales, has been utilized to better understand the motion of polythiophene chains during this thermochromic transition. Different solid‐state NMR analyses led to the determination of the relaxation rates for the main chain and the side chain as well as to the characterization of a twisting of the conjugated backbone chain during the thermochromic transition.magnified image

The printing of an efficient thermistor temperature sensor by using self-doped conducting polymers has been achieved. The use of a water-soluble polymer as the active material allows printing and processing in green solvents. The sensor showed a good sensitivity to temperature variations, with a temperature coefficient of resistance (TCR) of -1.3%. The sensor also exhibited a better stability and reversibility towards humidity compared to the state-of-the-art PEDOT:PSS.

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Photoacoustic sensing can be a powerful technique to obtain real-time feedback of laser energy dose in treatments of biological tissue. However, when laser therapy uses pulses with microsecond duration, they are not optimal for photoacoustic pressure wave generation. This study examines a programmable fiber laser technique using pulse modulation in order to optimize the photoacoustic feedback signal to noise ratio (SNR) in a context where longer laser pulses are employed, such as in selective retinal therapy. We have demonstrated with a homogeneous tissue phantom that this method can yield a greater than seven-fold improvement in SNR over non-modulated square pulses of the same duration and pulse energy. This technique was further investigated for assessment of treatment outcomes in leporine retinal explants by photoacoustic mapping around the cavitation-induced frequency band.