Title

Inkjet Printing of Metal Nanoparticles and Conducting Polymers onto Flexible Substrates and their Applications

Date of Completion

January 2010

Keywords

Chemistry, Polymer|Nanotechnology|Engineering, Materials Science

Degree

Ph.D.

Abstract

The inkjet printing of inorganic metal nanoparticles and conducting polymers is a popular fabrication method owing to its promising potential application in flexible electronics, e.g., for the fabrication of inkjet-printed silver (Ag) metal nanoparticle electrodes and inkjet-printed conducting polymers consisting of poly(3,4-ethylenedioxythiophene) (PEDOT) doped with poly(styrene sulfonate) (PSS).^ Four major challenges that are faced during fabrication, namely, printed line bulging, non-uniform line formation, low conductivity, and adhesion (peel-off) have been solved by controlling the drop spacing between ink drops, the drop frequency, and the substrate temperature. ^ The mechanical properties of inkjet printed Ag metal nanoparticle electrodes and inkjet printed PEDOT:PSS conducting polymers have been investigated using a nanoindentation technique. ^ The electrical conductivities of inkjet-printed Ag metal nanoparticle electrodes and inkjet-printed PEDOT:PSS conducting polymers have been measured using a four-line probe method. ^ The biosensor for the detection of antibodies to a peptide allergen based on an inkjetprinted Ag metal nanoparticle electrode has been successfully demonstrated on a flexible polyimide polymer substrate. The inkjet-printed Ag metal nanoparticle electrode on a flexible polymer substrate, exhibits distinct advantages in terms of simplicity of preparation, cost effectiveness, and reproducibility.^ This impedance biosensor shows good sensitivity and operational stability, demonstrating a promising possibility of the application of Ag metal nanoparticles and biological molecules to fabricate bio-electronic devices for the detection of antibodies to a peptide allergen on a flexible polymer substrate using a low-cost and very simple inkjet printing technology that reduces the use of raw materials.^ This thesis also describes photopattemed electrochromic conjugated nanofibers, which showed a reversible color change from dark green to dark orange in the oxidized and reduced (neutral) states, respectively. Photopatterning techniques coupled with electrostatic spinning processes have enabled the control of conjugated nanofiber patterns in the micron scale.^ This demonstrated that poly(norbornene—terthiophene) polymer nanofibers can act as an electrochromic layer in the fabrication of conjugated electrochromic devices consisting of nanofibers on an ITO-coated poly(ethylene terephthalate) (PET) substrate.^ The significance of this fabrication method is that it can be used to pattern conjugated electrospun nanofibers on ITO-coated poly(ethylene terephthalate) (PET) substrates using current industrial photolithography techniques. ^