NUS Graduate School for Integrative Sciences and Engineering

Seeram RAMAKRISHNA

Supervisor
Research Areas
Brief Description of Research
1. Nanoparticles & Nanomaterials
2. Self-assembled Nanostructures
3. Functional materials

 

Electrospun smart materials for wearable/flexible electronics
Background and Problem statement
Recent studies show that piezoelectric and triboelectric generators have provided an effective approach to generating electricity by harvesting the body’s energy. Thus, the technological realization of wearable triboelectric generators harvesting the mechanical energy induced by the activity of the human body is attractive because of their promising applications in wearable multifunctional intelligent systems.
However, the low electrical conductivity, the low electrical stability, and the low compatibility of current electronic textiles (e-textiles) and clothing restrict the comfortable and aesthetic integration of wearable generators into human clothing. Conducting polymers (polyanilin and polypyrrole) have been coated on cotton fabric by in situ oxidative polymerization. It was found that these fabrics had excellent UV-protection properties and the intact textile characteristics of the fabric coated with PPy were protected and improved, whereas the characteristics of the fabric coated with PAni were inferior. The resistance values of the cotton fabrics coated with PAni and PPy were found to be 350 and 512 Ω, respectively, whereas the bare fabric had a resistance value higher than 109 Ω. The average electromagnetic shielding efficiency and average absorption values of the cotton fabrics coated with PAni, PPy, and bare fabric were determined to be 3.8 dB and 48%, 6 dB and 50%, 0.26 dB and 2%, respectively.
Methods and Approach

  • The functional porous organic-inorganic polymer nanomaterials are expected to be extremely economic and environmental friendly.
  • The novel porous polymer nanomaterials expected to have high surface area and high thermal stability.
  • New multifunctional Polymerized ILs (di/tri/tetra-cationic ILs) will be synthesized by using different types of central cores having two or more cationic moieties for each center/backbone with different types of alkoxy or alkyloxyalkyl groups and substituted pyridyl or imidazolium rings to promote structure flexibility, solubility, stability, hydrophobic, and asymmetric in nature.
  • Electrospinning conducts to prepare the electrode membranes and to fabricate the piezoelectric device.
  • By utilizing these excellent smart e-textiles, we can fabricate pizoelectric generators that are able to provide stable power by harvesting the mechanical energy induced by low-frequency friction. Because of the high compatibility of the smart e-textiles and clothing, an electricity-generating glove that can generate energy from the action of the fingers as a proof of concept for wearable, self-powered devices, which will support the development of wearable electronics. The simple and scalable fabrication process, high conductivity, the high stability, and the compatibility with human clothing of the smart e-textiles are characteristics that make them important for the development of smart wearable electronics.

Research Project: Electrospun smart materials for wearable/flexible electronics