Bending piezoelectricity in a microbially produced poly-beta-hydroxybutyrate

Area of Science:

• Biomaterials Science
• Polymer Science
• Piezoelectric Materials

Background:

• Poly-beta-hydroxybutyrate (PHB) is a biodegradable polymer synthesized intracellularly by various bacteria.
• Optically active polymers are of interest for their unique physical and chemical properties.
• Piezoelectricity in biopolymers is an emerging area with potential applications in biosensors and actuators.

Purpose of the Study:

• To investigate the piezoelectric properties of oriented poly-beta-hydroxybutyrate (PHB) films.
• To quantify the bending piezoelectric effect in PHB.
• To compare the piezoelectric response of PHB with known biological materials like bone.

Main Methods:

• Production of poly-beta-hydroxybutyrate (PHB) in bacterial cytoplasm.
• Fabrication of oriented films from PHB.
• Measurement of the bending piezoelectric effect, specifically the coefficient relating electrical polarization to stress gradient.

Main Results:

• An optically active polymer, PHB, was successfully produced and formed into oriented films.
• The bending piezoelectric effect was clearly observed in the oriented PHB films.
• The piezoelectric coefficient was measured to be approximately 10(-18) Cm/N, similar to values reported for bone.
• Anisotropy in the piezoelectric coefficient was observed, indicating directional dependence of the effect.

Conclusions:

• Oriented poly-beta-hydroxybutyrate (PHB) films exhibit a measurable bending piezoelectric effect.
• The piezoelectric properties of PHB are comparable to those of bone, suggesting its potential as a biomimetic material.
• The observed anisotropy highlights the importance of film orientation for maximizing piezoelectric performance in PHB.