Paper Number
PO13 

Session
Poster Session

Title
Direct ink writing of cellulose nanofibrils-graphene hydrogels: Rheological and morphological study

Presentation Date and Time
October 12, 2022 (Wednesday) 6:30

Track / Room
Poster Session / Riverwalk A

Authors (Click on name to view author profile)

  1. Erfanian, Elnaz (University of Calgary)
  2. Kamkar, Milad (University of British Columbia)
  3. Rojas, Orlando J. (The University of British Columbia, Chemical and Biological Engineering)
  4. Sundararaj, Uttandaraman (University of Calgary)

Author and Affiliation Lines (in printed abstract book)
Elnaz Erfanian1, Milad Kamkar2, Orlando J. Rojas2 and Uttandaraman Sundararaj1
1University of Calgary, Calgary, Alberta T2N 1N4, Canada; 2University of British Columbia, Vancouver, Canada

Speaker / Presenter 
Erfanian, Elnaz

Keywords
additive manufacturing; biomaterials; polymer sustainability

Text of Abstract
Direct ink writing (DIW) method addresses the ever-accelerating demands on translating the inherent physical and chemical features of 2D nanomaterials such as graphene into 3D topologies and geometries. Graphene precursor for formulation of conductive graphene-based inks has been synthesized in the form of graphene oxide (GO), which is dispersible in water due to its oxygen-containing functional groups. However, functional groups of GO weaken electrical conductivity, requiring post-printing processes such as chemical, thermal, and microwave reduction. Even though pristine graphene (PG) possesses high conductivity, improving the dispersion quality of the PG nanomaterials and engineering the rheological properties of their aqueous-based inks is the main challenge in DIW of structures with high printing fidelity. To address the mentioned challenges, we worked toward engineering the colloidal properties of the custom-synthesized PG nanomaterials-based inks with addition of bio-based (2,2,6,6-tetrame- thylpiperidin-1-yl)oxidanyl (TEMPO)-oxidized cellulose nano- fibrils (TOCNF) as rheological modifier for high resolution 3D printing, realizing application in advanced electronics and sensors. The presence of TOCNF in the aqueous PG suspension facilitated the printability of the inks into pre-designed shapes by controlling rheology profiles that were suitable for processability and shape retention. It is shown that a high printing fidelity is significantly dependent on the TOCNF and PG concentration. By adjusting the relative fraction of PG and TOCNF, it is possible to control the density, the microstructure, and thus the final properties of the printed materials.