Doctor of Philosophy
Mechanical and Materials Engineering
3D printing has emerged as a powerful additive manufacturing technique and becomes as a viable alternative to conventional manufacturing processes in an increasing number of applications. Thus, the development of printable materials also continues to expand, while polymers are still the most utilized materials in 3D printing. There is a great advance for developing polymers with versatile mechanical and chemical properties. However, the end-use products are demanding various functions. It is imperative to develop functional 3D printed polymeric materials to achieve enhanced functionalities.
Usually, one polymer can meet one specific application. This has considerably limited the capability of 3D printing technology, especially for the photopolymerization based 3D printing. To overcome the challenges, I propose to advance the initiator integrated 3D printing technology to a more universal approach by introducing various active groups into polymer resins to fabricate functional materials and devices, together with a facile post-printing surface modification process. This allows polymeric structure to be metallized for electronics applications.
The strategy of this technology is using a bioinspired approach to engineer seed components into 3D printing resins, which allows the printed structures to possess the ability of functionalization. Dopamine and modified-dopamine are incorporated into water-soluble and lipid-soluble 3D printing resins respectively. After printing, the dopamine-integrated structures serve as active seeds to assist the following metallization process. Naturally derived polyphenols are also integrated into 3D printing resins, providing the customized resin with the capability of metallization, along with other functional properties development. Through secondary reactions, the applications of functional electronics fabrication, water treatment, surface hydrophilization and hydrophobization are demonstrated. Beside materials development, a dual-light 3D printing technology is developed as a 3D co-printing method, which is employed to fabricate 3D printed electronics with a customized 3D printing resin integrated with metal precursors.
In summary, a central strategy is to incorporate active chemical groups with desired functionalities, like high-binding ability, reducing ability, and etc., to develop new 3D printing materials for creation of functional surfaces of the 3D printed objects. This technology allows one 3D printing polymer to possess the capability of providing multiple specific applications through simple post-printing processes.
Summary for Lay Audience
3D printing is becoming an important manufacturing technique to manufacture complex structures that can’t be realized by conventional manufacturing processes. Thus, more and more new materials are developed to meet the demands. However, the end-use applications are not always fixed, which is still demanding more development.
Polymers are still the most popular materials in 3D printing industry, while one polymer can often only meet one specific application. This will require to develop a variety of new materials, along with corresponding printing techniques to meet the need. This is not only time consuming, but also lead to more technique hurtles, even increase the environmental burden.
A feasible technology is to incorporate active seed components into 3D printing resin. After printing, the printed structure will have functional chemical groups on the surface to develop new functions. In this study, dopamine, modified-dopamine and polyphenols are integrated into different kinds of 3D printing resins. The parameters are optimized not to affect the printability. Finally, newly developed 3D printing materials are able to be metallized or develop various other desired functions.
A dual-light 3D printing technology is also developed in this study, with one light for structure building, the other for conductive traces fabrication. With the unique technology, a 3D co-printing technology is developed for 3D printed electronics application.
Xiao, Junfeng, "Metallization Process for 3D Printed Electronics: from i3DP II to 3D Co-printing Technology" (2021). Electronic Thesis and Dissertation Repository. 7668.