Modeling of photo-thermo-sensitive hydrogels by applying the temperature expansion analogy

Research output: Contribution to journalResearch articleContributedpeer-review


Hydrogels are an outstanding material for sensor and actuator applications, for example, chemosensors and microfluidics, and have been extensively studied in both, experiments as well as in modeling within the last years. The theoretical investigations of hydrogels are key factors for the development of new hydrogel-based concepts in research and engineering. The recent approaches in modeling of the light-sensitive behavior of hydrogels are often complicated and very detailed. Commonly, they are based on the Helmholtz free energy function within a continuum-mechanical framework. In contrast, the Stimulus Expansion Model (SEM) is a simple and very effective approach to embed the swelling properties of a hydrogel into a continuum mechanical framework. Originally, the SEM was applied to chemical stimulation processes based on available experimental swelling curves. The current work provides an extension of the SEM for photo-thermo-sensitive hydrogels. The present approach considers (i) the attenuation of light by applying Lambert-Beer’s law as well as (ii) the energy transfer of light into heat. In this study, PNIPAm hydrogels with incorporated light-absorbing particles of copper-chlorophyllin are investigated. To demonstrate the capabilities of the presented approach, the effect of the variation of (i) light power, (ii) particle volume fraction, and (iii) ambient temperatures on the swelling behavior is analyzed. The obtained results show an excellent correlation with experimental results from literature. Concluding, the extended Stimulus Expansion Model provides further opportunities to design and simulate photo-thermo-sensitive hydrogels for engineering applications.


Original languageEnglish
Pages (from-to)2268-2279
Number of pages12
JournalJournal of intelligent material systems and structures
Issue number19
Publication statusPublished - 24 Apr 2023

External IDs

Scopus 85153608885
WOS 000974732100001


Research priority areas of TU Dresden

Subject groups, research areas, subject areas according to Destatis


  • Hydrogels, modeling, photo-thermo-sensitive gels, stimulus expansion model, thermal stimulation, Stimulus expansion model, Photo-thermo-sensitive gels, Modeling, Thermal stimulation