Sustained and triggered release by microencapsulation
Licentiate thesis, 2021

Uncontrolled growth of microorganisms is problematic in areas ranging from wound care to aquaculture and ship hulls. In chronic and hard-to-heal wounds, a bacterial biofilm can impair wound healing. The growth of marine microorganisms, so-called biofouling, on equipment used in aquaculture can decrease productivity and thereby result in a loss of revenue. To counteract these problems and minimize microbial growth, antimicrobial substances have been developed. For efficient use of these antimicrobial substances that enables long-term protection without excessive use, their release from materials should be controlled.

In this work, microencapsulation was used as a means of controlling the rate at which a model hydrophobic substance was released in two different ways. A slow sustained release microparticle system with a complete release over a period of weeks was developed. These microcapsules were also incorporated into cellulose fibers, to produce a nonwoven material possessing controlled release properties. As a complement to this, a fast triggered release system was developed where a significant release could be seen within minutes of the trigger event.

Through a combination of these two types of controlled release, a hypothetical release profile could be tailored to fit specific applications. The triggered release microparticles could initially increase the antimicrobial concentration above a certain effective concentration, and the sustained release microparticles would maintain the concentration above the effective concentration for a prolonged time. The use in a nonwoven fiber material was illustrated in this work, although use in e.g. continuous fibers or painted coatings could also easily be conceived.


controlled release


solution blown

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Viktor Eriksson

Chalmers, Chemistry and Chemical Engineering, Applied Chemistry

Hanna Ulmefors, Ting Yang Nilsson, Viktor Eriksson, Gustav Eriksson, Lars Evenäs, and Markus Andersson Trojer. Solution-spinning of a collection of micro- and nanocarrier-functionalized polysaccharide fibers

Viktor Eriksson, Jules Mistral, Ting Yang Nilsson, Markus Andersson Trojer, and Lars Evenäs. Microencapsulation for controlled release of model active substances from cellulose nonwovens

Formulation of polyphthalaldehyde microcapsules for immediate UV-light triggered release

Journal of Colloid and Interface Science,; Vol. 579(2020)p. 645-653

Journal article

Smart, benign and synergistic antifouling cocktails for achieving a non-toxic environment: formulation and ecotoxicological evaluation

Formas (2018-02284), 2018-12-01 -- 2022-11-30.

Subject Categories

Polymer Chemistry

Textile, Rubber and Polymeric Materials

Other Chemistry Topics


Chalmers Materials Analysis Laboratory

Areas of Advance

Materials Science



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