Direct joining and debonding on-demand of polymers through surface modification and metal ion interaction

Günther, Roman

doi:10.3929/ethz-b-000617606

Publication type:	Doctoral thesis
Title:	Direct joining and debonding on-demand of polymers through surface modification and metal ion interaction
Authors:	Günther, Roman
Advisors / Reviewers:	Niederberger, Markus Brändli, Christof Caseri, Walter Heuberger, Manfred Tervoort, Theo
DOI:	10.3929/ethz-b-000617606
Extent:	X, 154
Issue Date:	Jun-2023
Publisher / Ed. Institution:	ETH Zurich
Publisher / Ed. Institution:	Zurich
Language:	English
Subjects:	Bonding; Debonding on demand; Surface roughness; Polymer surface modification; Polymer surface analysis
Subject (DDC):	620.11: Engineering materials
Abstract:	This work focuses on the development of a novel method for joining and residue-free separation of polymer surfaces that support polymer recycling and enables the bond-ing of incompatible polymers. The technology presented employs polymer surface modification to generate functional groups that enable reversible joining through intermolecular interactions between two rigid, macroscopic polymer surfaces. The research consists of four segments, each emphasizing distinct elements of the join-ing process. The first section, which deals with the contact mechanics and adhesion of macro-scopic surfaces, deepened the understanding of the interactions between polymer surfaces by analyzing topographically defined polystyrene surfaces produced via hot pressing. Using atomic force microscopy and a specially developed measuring clamp, surface adhesion was investigated in relation to topography and oxygen plasma treatment and compared with established adhesion models (Johnson-Kendell-Roberts and Pastweka-Robbins adhesion criterion). It was determined that these models inadequately represent complex polymer surface interactions and are only conditionally suitable for predicting polymer adhesion. Thus, model modifications are required, to which the presented techniques could contribute. In the second section, the potential of low-pressure plasma treatment for modifying polystyrene and polyamide 12 surfaces was examined. By introducing functional groups into the polymer surface, the surfaces could be firmly bonded together by pressing without the use of adhesives. However, with water as a trigger, the bonds could be dissolved again within seconds. This separation mechanism suggests that the joining forces could be mainly based on hydrogen bonds. After dissolving the bond in water, the surfaces could be reconnected by renewed plasma treatment. The third section investigated the role of acrylic acid and copper(II) ions on the adhe-sion and separation of bonded polystyrene surfaces. Oxygen plasma modified and acrylic acid grafted (wet chemical process) surfaces were treated with copper(II) ions to analyze the effects of surface treatment, ions, and joining temperature on adhesive force and separation. Acrylic acid grafted samples exhibited enhanced adhesion due to an increased number of functional groups compared to surfaces treated with oxy-gen plasma only. Acrylic acid grafting also allowed for more significant copper(II) ions loading, which increased adhesion. The bond strength could be controlled by varying the joining temperatures and the copper(II) ion loading. The separation time of the joint could also be altered by controlling these parameters from seconds to insol-ubility in water. Nevertheless, all joints could be separated with EDTA and ultrasound. In the fourth section, the feasibility of transferring acrylic acid grafting to an easily scalable inline process was explored. Atmospheric plasma was used to apply acrylic acid directly to the surface, eliminating the need for a wet chemical process. The adhesion of the applied acrylic acid layer was found to be dependent on the underly-ing polymer, which was particularly noticeable when the polymers were separated in water. Joints, where polyamide 12 was involved, exhibited higher water separation resistance. In addition, the effect of different metal ions on adhesion and joint sepa-ration between treated surfaces was investigated. No significant adhesion enhance-ment between surfaces was achieved in the conducted experiments. However, in-creased resistance to separation with water was found in all cases, with copper show-ing the most significant effect. In this work, an innovative joining technology that enables the joining and separation of polymer surfaces for improved recycling without adhesives was presented. The technology integrates the joining capability into the polymer surface and has demon-strated its potential for industrial applications. Critical factors for successful joining encompass surface roughness, surface modification, the presence of ions on the surface, and joining temperature. When appropriately combined, these parameters enable strong, reversible joining between polymers, allowing easy separation by water or EDTA solutions. This research explores a new direction with considerable implica-tions for the polymer and adhesive industry, supporting polymer recycling and foster-ing sustainability. To further advance the technology developed in this study, future research should focus on broadening the range of polymers and separation methods, improving the hot pressing process, refining adhesion models, investigating alternative ligands and grafting techniques, optimizing adhesion strength and separation capabilities using metal ions and nanoparticles, improving the atmospheric plasma grafting process, and demonstrating technology transferability into applications. Weniger anzeigen
URI:	https://digitalcollection.zhaw.ch/handle/11475/28297
License (according to publishing contract):	Licence according to publishing contract
Departement:	School of Engineering
Organisational Unit:	Institute of Materials and Process Engineering (IMPE)
Appears in collections:	Publikationen School of Engineering

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Günther, R. (2023). Direct joining and debonding on-demand of polymers through surface modification and metal ion interaction [Doctoral dissertation, ETH Zurich]. https://doi.org/10.3929/ethz-b-000617606

Günther, R. (2023) Direct joining and debonding on-demand of polymers through surface modification and metal ion interaction. Doctoral dissertation. ETH Zurich. Available at: https://doi.org/10.3929/ethz-b-000617606.

R. Günther, “Direct joining and debonding on-demand of polymers through surface modification and metal ion interaction,” Doctoral dissertation, ETH Zurich, Zurich, 2023. doi: 10.3929/ethz-b-000617606.

GÜNTHER, Roman, 2023. Direct joining and debonding on-demand of polymers through surface modification and metal ion interaction. Doctoral dissertation. Zurich: ETH Zurich

Günther, Roman. 2023. “Direct Joining and Debonding On-Demand of Polymers through Surface Modification and Metal Ion Interaction.” Doctoral dissertation, Zurich: ETH Zurich. https://doi.org/10.3929/ethz-b-000617606.

Günther, Roman. Direct Joining and Debonding On-Demand of Polymers through Surface Modification and Metal Ion Interaction. ETH Zurich, June 2023, https://doi.org/10.3929/ethz-b-000617606.