Regular facade cleaning is essential for maintaining the value of an object. In particular cleaning of porous facade materials is challenging because stubborn soils often penetrate deeply into these construction materials. Removal of such strongly adhering soils by using currently available cleaning methods means high personnel costs and time.

A new method for economical cleaning of porous facade materials by using segregating gel networks was therefore developed in the research project. Such segregating gel networks are composed of amphiphilic polymers and a liquid phase (water or soil-specific detergent).

Segregating gel networks change their cross-linking state in response to external stimuli (me-chanical impact, UV irradiation). As a result, they completely wet and penetrate facade mate-rials during application (slightly physically cross-linked state due to mechanical stress during application) and show good adhesion during exposure (strongly physically cross-linked state due to absence of mechanical stress after application).

Gel networks can be chemically cross-linked under diffusion-controlled segregation by surface initiated polymerization (chem-ically cross-linked state induced by UV irradiation). Chemically cross-linked segregating gel networks can be manually or mechanically removed from facade surface as solid film by low mechanical stress.

Cleaning effect of segregating gel networks is based on amphiphilic character of polymers, which can slide between facade material and soil and remove soil from facade material under incorporation into gel network. Incorporated soil is removed from facade material during diffusion-controlled segregation.

High soil removal and simple separation of detergent and soil from facade materials is achieved using segregating gel networks providing an effective and gentle facade cleaning.

The research report is available on request from FRT.