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Liu, Yaan (2020) Additive manufacture of three dimensional metal-polymer nanocomposites through two-photon fabrication. PhD thesis, University of Nottingham.

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Abstract

Two-photon fabrication is an attractive additive manufacturing (AM) technique that allows the production of 3D objects with high resolution down to 100 nm. It has been applied to fabricate nano-photonics, microelectromechanical systems (MEMS), microelectronics, microfluidic devices and biochips. In this thesis, complex 2D and 3D gold-, silver- and copper-polymer nanocomposites were additive manufactured for the first time through two-photon polymerisation (TPP) and two-photon reduction (TPR) in a single step. The research aims to investigate the printability of using simultaneous photopolymerisation and photoreduction to produce 3D metal-polymer nanocomposites that could be potentially applied to microelectronics, metamaterials and SERS (surface-enhanced Raman spectroscopy). A series of formulations were developed and prepared to assess the printability. The relationship between materials composition or processing parameter and final structures were characterised and investigated. The potential applications of fabricated structures were evaluated and discussed.

3D gold-polymer nanostructures were fabricated through the two-photon based manufacturing method. Two kinds of triacrylate based monomers of similar structure were compared and chosen to fabricate gold-polymer nanocomposites. Irgacure 369 was used as a photoinitiator. When gold salt was added, additional photoinitiator was required to provide more free radicals for photoreduction because there was a competition between TPP and TPR. The adding of two-photon sensitive dye, tris(2,2’-2 bipyridyl) dichlororuthenium (II) hexahydrate, can stabilise the fabrication process,

allowing for the fabrication of 3D gold-polymer nanocomposite structures.

Silver-polymer nanocomposites were developed through simultaneous photopolymerisation and photoreduction for the first time. A series of materials were assessed to produce silver-polymer nanocomposites. A phase-transfer protocol that transferred silver ions from the water phase to toluene phase enabled good mixing of PETA (pentaerythritol triacrylate) as a monomer, Irgacure 369 as a photoinitiator and coumarin 30 as a photosensitive dye. 2D and 3D complex silver-polymer nanostructures were fabricated by TPL (Two-photon lithography). By adding

coumarin 30 photosensitive dye, better light interaction, higher resolution of line width and more uniform size and distribution of silver NPs (nanoparticles) were observed. The average size of silver particles well distributed in the fabricated structures was 5.8 ± 1.5 nm.

An initial investigation on the fabrication of copper-containing nanostructures through two-photon fabrication was conducted. 3D copper-polymer nanocomposites were

successfully obtained.

The phase transfer method used in this research could be applied in the synthesis of a variety of metal-polymer functional materials through simultaneous photopolymerisation. The successful additive manufacture of complex 2D (twodimensional) and 3D (three-dimensional) metal-polymer nanocomposite structures provides potential to be used in photonics, metamaterials, plasmonics, electronics, catalysis and bio-sensing.

Item Type:	Thesis (University of Nottingham only) (PhD)
Supervisors:	Wildman, Ricky Tuck, Christopher Hague, Richard
Keywords:	Additive manufacturing, Metal-polymer nanocomposites, Two-photon fabrication
Subjects:	T Technology > TS Manufactures
Faculties/Schools:	UK Campuses > Faculty of Engineering > Department of Mechanical, Materials and Manufacturing Engineering
Item ID:	61370
Depositing User:	Liu, Yaan
Date Deposited:	31 Dec 2020 04:40
Last Modified:	31 Dec 2020 04:40
URI:	https://eprints.nottingham.ac.uk/id/eprint/61370

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