Piezoelectricity of Poly(L-lactic Acid) Composite Film with Stereocomplex of Poly(L-lactide) and Poly(D-lactide)

Abstract

The piezoelectricity of a film of the eco-material poly(L-Lactic acid) (PLLA) with high transparency and flexibility has been noted for its possibility of application to new types of devices used in mobile equipment. However, for its application, there are many difficult problems to be solved, because the PLLA film has poor thermal stability. To change the high-order structure of the PLLA film, thus realizing an improvement in the temperature dependence of its piezoelectricity, a composite film with a stereocomplex crystal (SC) formed from PLLA and poly(D-lactide acid) (PDLA) molecules was fabricated. As a result, we obtained a composite film with a stable piezoelectric temperature dependence compared with a pure PLLA film. To analyze its piezoelectric temperature dependence, we first observed the high-order structure of the composite film using a polarized microscope (POM). However, we did not find any difference between the high-order structures of the composite film and the pure PLLA film. In contrast, from observation by atomic force microscopy (AFM), it was found that the grain structure in the composite film became more homogeneous than that in the pure PLLA film. These experimental results indicate that, by changing the high-order structure through a compound with SC, the external stress always has a constant effect over a wide temperature range and, as a result, the induced polarization is constant in the composite film. Thus, the composite film shows excellent thermal stability of piezoelectricity compared with the pure PLLA film.

Piezoelectric Biomaterials for Sensors and Actuators

“…The electrospinning process can also align the CO bond to create piezoelectric PLLAs as seen in Figure d (right). PLLA is a transparent and very flexible plant‐derived polymeric material, and is considered suitable for applications in mobile devices as an environmentally friendly, flexible, transparent, piezoelectric thin film . However, the practical application of PLLA is limited because its piezoelectric constant is much lower than that of inorganic piezoelectric materials such as PZT.…”

Piezoelectric poly(lactide) stereocomplexes with a cholinium organic ionic plastic crystal

“…Yoshida et al reported a slight improvement in the piezoelectric modulus (d 0 ) below T g (65-70 1C) in a PLLA composite film with only 10% SC crystals. 42 We have thus looked at the effect of [Ch][DHP] on the piezoelectric response of the membranes measured using piezoresponse force microscopy (PFM). No local piezoelectric activity is observed in PLA (Fig.…”

Pressure-Sensitive Touch Panel Based on Piezoelectric Poly(L-lactic acid) Film

“…PLLA does not exhibit pyroelectricity because it does not have an intrinsic polarization. [16][17][18][19][20][21][22] PVDF is a polymer that belongs to the ferroelectric group, and exhibits pyroelectricity because it has an intrinsic polarization. Figure 2 shows the time dependence of the amount of electric charge generated in PLLA and PVDF films due to heat.…”