Inkjet-printed Polyvinyl Alcohol Multilayers

Summary

An inkjet printer was used to manufacture polyvinyl alcohol multilayers. Polyvinyl alcohol water-based ink was formulated, and the main physical properties were investigated.

Abstract

Inkjet printing is a modern method for polymer processing, and in this work, we demonstrate that this technology is capable of producing polyvinyl alcohol (PVOH) multilayer structures. A polyvinyl alcohol aqueous solution was formulated. The intrinsic properties of the ink, such as surface tension, viscosity, pH, and time stability, were investigated. The PVOH-based ink was a neutral solution (pH 6.7) with a surface tension of 39.3 mN/m and a viscosity of 7.5 cP. The ink displayed pseudoplastic (non-Newtonian shear thinning) behavior at low shear rates, and overall, it demonstrated good time stability. The wettability of the ink on different substrates was investigated, and glass was identified as the most suitable substrate in this particular case. A proprietary 3D inkjet printer was employed to manufacture polymer multilayer structures. The morphology, surface profile, and thickness uniformity of inkjet-printed multilayers were evaluated via optical microscopy.

Introduction

Polyvinyl alcohol is semicrystalline, artificial, non-toxic, water-soluble, insoluble in most organic solvents, biodegradable, and biocompatible in human tissues and has excellent gas-barrier properties¹. Furthermore, due to its many useful properties, PVOH is widely used in a large number of applications. Nowadays, PVOH is used in: the manufacture of cleaning and detergent products, the food packaging industry, water treatment, textile, agriculture, and construction (as additives)¹. However, PVOH has recently attracted an increased amount of attention for pharmaceutical uses² (i.e., drug....

Protocol

1. Ink Formulation

1. Prepare the solution for IJP by dissolving polyvinyl alcohol (8 wt.% PVOH in water) in purified water heated to 60 °C.
2. Add 10 g of mono-propylene glycol (MPG) (10 wt.% mono-propylene glycol in water), as a humectant, to the solution.
   NOTE: The role of the humectant is to prevent blockages in the printhead.
3. Stir the solution for several hours to ensure homogeneity and then filter it through a 5 µm filter to remove any particulates that might block the nozzles.
4. Visually assess the ink for homogeneity, especially for any incidence of sedimentation. If sedimentation is observed, then either stir....

Results

The physical properties of PVOH water-based ink, such as surface tension, viscosity/rheological behavior, pH, wetting, and time stability, were investigated. The viscosity of the ink used in this work was 7.5 cP, and the surface tension was 39.3 mN/m. Additionally, the formulated ink was neutral (pH 7), with the results summarized in Table 1.

Ink

Discussion

In this work, we successfully demonstrated the ability of inkjet printing technology to deposit polymer multilayers. The rheological behavior was investigated, and the experimental results demonstrate that the formulated ink displays pseudoplastic shear thinning behavior. Also, the PVOH ink is a neutral solution (pH 7) and shows good stability over time. Notably, it was successfully demonstrated that IJP technology is capable of producing polyvinyl alcohol multilayer structures, but further improvements in printing cover.......

Materials

List of materials used in this article

Name	Company	Catalog Number	Comments
Polyvinyl alcohol	PVOH Polymers Ltd, UK	Poval 4-88
Mono-propylene glycol	Sigma Aldrich, UK	W29004
DV2T viscometer	Brookfield, UK
Attension Theta Optical Tensiometer	Biolin Scientific, Sweden
HANNA pH meter	HANNA Instruments, UK
industrial Inkjet XYPrint100Z	Industrial Inkjet Ltd, UK
ContourGT-K 3D optical microscope	Bruker Corp, USA