title: Property enhancement of supramolecular polymers for 3D printing
Creators: name: Salimi, Sara
Publisher: name: University of Reading
Year: 2022

description: Supramolecular polymers are a class of polymers made up of low molecular weight 
polymers/oligomers which self-assemble through different intermolecular interactions and 
form a pseudo-high molecular weight polymer. Supramolecular polymers are recently finding 
ways into different applications in 3D printing. These materials can be used as inks for 
different type of 3D printers. The main advantage of supramolecular polymers over 
conventional polymers is their relatively low processing temperature. Indeed, the dissociation 
of low energy supramolecular interactions results in decrease in their viscosity hence they can 
be deposited exploiting a more efficient process. In Chapter 1 is gathered a small review of 
supramolecular polymers and their application in 3D printing as well as a discussion about 
their mechanical properties.
Next, an example application of a supramolecular polyurethane with dynamic nature in 3D 
printing is investigated. In Chapter 2, a supramolecular polyurethane is formulated with 
poly(ethylene glycol) and paracetamol and was hot-melt extruded to give rise to a drug-release implant. It was predicted that the implant is capable of fully releasing the drug in 8.5 
months. Unfortunately, deformation of the printed implants was observed after the release 
experiment. In order to overcome this undesirable properties, Chapter 3 is investigating the 
reinforcement of such supramolecular polyurethanes. Utilisation of a bis-urea compound 
which is synthesised in situ during the formation of the supramolecular polyurethane as a by-product was studied as the reinforcing filler material. This method of reinforcement was 
studied on a variety of supramolecular materials and their properties as well as their 
processability and printability under extrusion condition were investigated. The same concept 
was also utilised in order to design a mechanical gradient part using dual-feed extrusion 
printer in Chapter 4. To realise the design, supramolecular polymer as well as it reinforced 
analogous were synthesised. These materials were then mixed at different ratios using a 3D 
printer to produce materials with varied mechanical properties along one dimension of the 
printed bar. It was shown that upon utilisation of such design, it is possible to direct the 
applied stress/strain to a part into a desired section.
Additionally, in Chapter 5 reinforcement of supramolecular polymers using silica 
nanoparticles as inorganic filler was investigated. The effect of surface functionality of the 
silica nanoparticles on the mechanical properties of the final composite was inspected. Then, 
incorporation of a type of silica nanoparticles with a reactive functionality into a 
supramolecular polymer using a reactive extrusion printer was also studied and generation of 
a nanocomposite with superior mechanical properties through formation of secondary 
network was observed. In addition, in order to introduce further functionality to a 
supramolecular polymer with adhesion ability, iron (III) oxide nanoparticles exploited. 
Chapter 6 outlined the details of this study. It is demonstrated that the supramolecular 
polyurethane composite adhesive can bound or debound the substrates when subjected to 
oscillatory magnetic field. Upon exposure to the field, the magnetic particles generate heat 
internally which is adequate for dissociation of the supramolecular polymer and hence the 
loss of its viscosity.