Polymers in Inkjet Printing

Wheeler, Joseph; Yeates, Stephen G.

doi:10.1002/9783527684724.ch5

Cited by 8 publications

(3 citation statements)

References 44 publications

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“…The calculation is based on the known viscosity of the bare solvent and intrinsic viscosity. Rouse theory considers a similar calculation, but the equation for the relaxation time contains one more constant (6/π 2 ) and considers a viscosity-average molecular weight. , However, both approaches are valid for infinite diluted polymer solutions only (below the first critical concentration c *) (in other words, these approaches are limited and can be useful for the printing of trace concentrations of a polymer).…”

Section: Resultsmentioning

confidence: 99%

Inkjet Printability Assessment of Weakly Viscoelastic Fluid: A Semidilute Polyvinylpyrrolidone Solution Ink Case Study

et al. 2021

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Here, we present an integrated approach to the weakly viscoelastic fluid printability assessment by using global dimensionless criteria (DC). The problem was studied on a model semidiluted polyvinylpyrrolidone water-based ink. For the study purpose, the ink composition was kept as simple as possible. First, the solution density, viscosity, and surface tension were determined. Obtained data were used for testing limitations of DC printability diagrams already available for Newtonian fluids. A replotted version of the original Kim and Baek’s map was developed emphasizing the importance of surface tension in the drop formation process. Another set of DC (e.g., Ec and De) was also used for a real evaluation of the viscoelasticity effect on both jetting conditions and drop formation. The polymer relaxation time as a crucial parameter for viscoelasticity was shown to be calculated using the Kuhn segment length rather than from Zimm and Rouse theories for diluted polymer systems. Then, a two-dimensional diagram using four DC (Oh and De with Ec and El as parameters) is proposed based on the famous McKinley’s work. The diagram describes the interplay of possible forces responsible for filament thinning and breakup processes. Obtained results were supported by further experiments involving drop ejection and formation, determination of critical polymer concentration, and others. The proposed diagram promises a useful initial step in further investigations of viscoelasticity of polymer compounds by inkjet printing.

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Section: Resultsmentioning

confidence: 99%

Inkjet Printability Assessment of Weakly Viscoelastic Fluid: A Semidilute Polyvinylpyrrolidone Solution Ink Case Study

et al. 2021

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“…Both viscosity and surface tension of the GM solution at the printing temperature of 28 °C (Figure S3, Supporting Information) are in the range of other liquids that can be processed by inkjet printing, although the surface tension is slightly higher than typical for most inks. [25,49,50] At the given temperature, the least nozzle clogging caused by solvent evaporation occurred, and drop formation was relatively stable. At lower GM concentrations, solutions were not viscous enough, and higher GM concentrations caused nozzle clogging.…”

Section: Wetting Of the Hydrogel Surfaces By Gelatin Methacryloyl Sol...mentioning

confidence: 99%

Soft Sub‐Structured Multi‐Material Biosensor Hydrogels with Enzymes Retained by Plant Viral Scaffolds

Grübel,

Wendlandt,

Urban

et al. 2023

Macromolecular Bioscience

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An all‐soft multi‐material combination consisting of a hydrogel based on poly(ethylene glycol) (PEG) coated with spatially defined spots of gelatin methacryloyl (GM) containing selectively addressable viral nanorods is presented, and its basic application as a qualitative biosensor with reporter enzymes displayed on the tobacco mosaic virus (TMV) bioscaffolds within the GM is demonstrated. Biologically inert PEG supports are equipped with GM spots serving as biological matrix for enzymes clustered on TMV particles preventing diffusion out of the gel. For this multi‐material combination, i) the PEG‐based hydrogel surface is modified to achieve a clear boundary between coated and non‐coated regions by introducing either isothiouronium or thiol groups. ii) Cross‐linking of the GM spots is studied to achieve anchoring to the hydrogel surface. iii) The enzymes horseradish peroxidase or penicillinase (Pen) are conjugated to TMV and integrated into the GM matrix. In contrast to free enzymes, enzyme‐decorated TMVs persist in GM spots and show sustained enzyme activity as evidenced by specific color reaction after 7 days of washing, and for Pen after 22 months after dry storage. Therefore, the integration of enzyme‐coupled TMV into hydrogel matrices is a promising and versatile approach to obtaining reusable and analyte‐specific sensor components.

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“…Where x is the mass loading as a percentage, (R 2 = 0.9999). The Newtonian behavior would be generally expected considering the relatively low molecular weight of the PVP used (55 kDa ~ 495 monomers) [582][583] , and low mass loadings of both PVP [582] and LBZA particulates (≤ 2.6 % mass) [434] . The low mass loadings and low molecular weight would have limited interactions, leading to a reduced ability for the ink to form any significant internal structure.…”

Section: Force Optimisation Experimentsmentioning

confidence: 99%

Flexographic printed nanogranular LBZA derived ZnO gas sensors: Synthesis, printing and processing

Lewis¹

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Within this document, investigations of the processes towards the production of a flexographic printed ZnO gas sensor for breath H2 analysis are presented. Initially, a hexamethylenetetramine (HMTA) based, microwave assisted, synthesis method of layered basic zinc acetate (LBZA) nanomaterials was investigated. Using the synthesised LBZA, a dropcast nanogranular ZnO gas sensor was produced. The testing of the sensor showed high sensitivity towards hydrogen with response (Resistanceair/ Resistancegas) to 200 ppm H2 at 328 °C of 7.27. The sensor is highly competitive with non-catalyst surface decorated sensors and sensitive enough to measure current H2 guideline thresholds for carbohydrate malabsorption (Positive test threshold: 20 ppm H2, Predicted response: 1.34). Secondly, a novel LBZA synthesis method was developed, replacing the HMTA by NaOH. This resulted in a large yield improvement, from a [OH-] conversion of 4.08 at% to 71.2 at%. The effects of [OH-]/[Zn2+] ratio, microwave exposure and transport to nucleation rate ratio on purity, length, aspect ratio and polydispersity were investigated in detail. Using classical nucleation theory, analysis of the basal layer charge symmetries, and oriented attachment theory, a dipole-oriented attachment reaction mechanism is presented. The mechanism is the first theory in literature capable of describing all observed morphological features along length scales. The importance of transport to nucleation rate ratio as the defining property that controls purity and polydispersity is then shown. Using the NaOH derived LBZA, a flexographic printing ink was developed, and proof-of-concept sensors printed. Gas sensing results showed a high response to 200 ppm H2 at 300 °C of 60.2. Through IV measurements and SEM analysis this was shown to be a result of transfer of silver between the electrode and the sensing layer during the printing process. Finally, Investigations into the intense pulsed light treatment of LBZA were conducted. The results show that dehydration at 150 °C prior to exposure is a requirement for successful calcination, producing ZnO quantum dots (QDs) in the process. SEM measurements show mean radii of 1.77-2.02 nm. The QDs show size confinement effects with the exciton blue shifting by 0.105 eV, and exceptionally low defect emission in photoluminescence spectra, indicative of high crystalline quality, and high conductivity. Due to the high crystalline quality and amenity to printing, the IPL ZnO QDs have numerous potential uses ranging from sensing to opto-electronic devices.

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Polymers in Inkjet Printing

Cited by 8 publications

References 44 publications

Inkjet Printability Assessment of Weakly Viscoelastic Fluid: A Semidilute Polyvinylpyrrolidone Solution Ink Case Study

Inkjet Printability Assessment of Weakly Viscoelastic Fluid: A Semidilute Polyvinylpyrrolidone Solution Ink Case Study

Soft Sub‐Structured Multi‐Material Biosensor Hydrogels with Enzymes Retained by Plant Viral Scaffolds

Flexographic printed nanogranular LBZA derived ZnO gas sensors: Synthesis, printing and processing

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