Frugal Imaging Technique of Capillary Flow Through Three-Dimensional Polymeric Printing Powders

Summary

The proposed technique will provide a novel, efficient, frugal, and non-invasive approach for imaging fluidic flow through a packed powder bed, yielding high spatial and temporal resolution.

Abstract

The development of novel imaging techniques of molecular and colloidal transport, including nanoparticles, is an area of active investigation in microfluidic and millifluidic studies. With the advent of three-dimensional (3D) printing, a new domain of materials has emerged, thereby increasing the demand for novel polymers. Specifically, polymeric powders, with average particle sizes on the order of a micron, are experiencing a growing interest from academic and industrial communities. Controlling material tunability at the mesoscopic to microscopic length scales creates opportunities to develop innovative materials, such as gradient materials. Recently, a need for micron-sized polymeric powders has been growing, as clear applications for the material are developing. Three-dimensional printing provides a high-throughput process with a direct link to new applications, driving investigations into the physio-chemical and transport interactions on a mesoscale. The protocol that is discussed in this article provides a non-invasive technique to image fluid flow in packed powder beds, providing high temporal and spatial resolution while leveraging mobile technology that is readily available from mobile devices, such as smartphones. By utilizing a common mobile device, the imaging costs that would normally be associated with an optical microscope are eliminated, resulting in a frugal-science approach. The proposed protocol has successfully characterized a variety of combinations of fluids and powders, creating a diagnostic platform for quickly imaging and identifying an optimal combination of fluid and powder.

Introduction

Inkjet-based binder jetting into powder media represents an important technology in additive manufacturing (3D printing). The binder jetting process begins with the deposition of functional fluids into powder media using a scanning inkjet printing process. Specifically, an inkjet print head translates over the powder surface, depositing the liquid binding agent onto a powder surface, and thereby forming a solid part in a layer-by-layer fashion¹. Inkjet-based binder jetting technologies generally include sand, metal powders, and polymeric powders. However, to expand the materials' space in binder jetting, a fundamental approach to investigat....

Protocol

1. Preparing the microfluidic flow cell

NOTE: For this protocol, a commercial microfluidic flow cell will be utilized. By using a commercial product that is designed for light penetration from an optical microscope, any challenges regarding brightfield illumination of the media will be minimized.

1. Start preparing the microfluidic flow cell by covering the outlet with parafilm to seal one end of the channel so that the empty flow cell may be packed with polymeric powder. Before starting the experiment, confirm that the microfluidic channel is clean and dry.
   1. Tape the metric paper ruler directly beneath ....

Results

In the section on analyzing data, the data for the time-lapsed images in Figure 3 illustrate the 75 wt% ethanol solution infiltrating the polycarbonate (PC) powder. Fluorescein was added to the solution to enhance the image quality for this publication. In the time-lapse images, the time-resolved process begins when the fluid is added to the inlet. Time, t, starts as soon as the fluid begins to penetrate the channel. The series of images demonstrates the progression of the fluid and.......

Discussion

The protocol that is provided is highly dependent on the material characteristics of the particles that are chosen. Material properties impacting flow include particle size distribution^{2,3,4,5,11,21}, particle surface roughness¹¹, chemical properties at the particle surface^2.......

Materials

List of materials used in this article

Name	Company	Catalog Number	Comments
µ-Slide I Luer	ibidi	80191	Microfluidic flow cell
Beaker	Southern Labware	BG1000-800	Glassware
CALIBRE 301-58 LT Natural Polycarbonate Resin	TRINSEO LLC	CALIBRETM 301-58 LT	Natural polycarbonate resin
Ethanol	Sigma Aldrich	1.00983	Solvent
Fume Hood	Kewaunee	Supreme Air LV Fume Hoods	Used with 92 FPM at 18" opening
iPhone 7 plus	Apple		Camera
Opaque 3D printed material			The CAD drawing is provided in the supplemental file
ORGASOL  2002 ES 6 NAT 3	ARKEMA	A12135	Polyamide powder
Pipet	VWR	10754-268	Disposable Transfer Pipet
Pipette	Globe Scientific Inc.	3301-200	Pipette that can hold 125 µL of fluid
Polystyrene	Advanced Laser Materials, LLC.	PS200	Polystyrene for sintering
Tracker			Video analysis and modeling tool
VariQuest 100 White Light Model 3-3700	FOTODYNE	3-3700	White light
Water			Distilled water