94 research outputs found
Nemateriālo aktīvu grāmatvedības metodoloģiskās problēmas Latvijas Republikā
Nonfluorinated hydrophobic surfaces
are of interest for reduced
cost, toxicity, and environmental problems. Searching for such surfaces
together with versatile processing, A200 silica nanoparticles are
modified with an oligodimethylsiloxane and used by themselves or with
a polymer matrix. The goal of the surface modification is controlled
aggregate size and stable suspensions. Characterization is done by
NMR, microanalysis, nitrogen adsorption, and dynamic light scattering.
The feasibility of the concept is then demonstrated. The silica aggregates
are sprayed in a scalable process to form ultrahydrophobic and imperceptible
coatings with surface topographies of controlled nanoscale roughness
onto different supports, including nanofibrillated cellulose. To improve
adhesion and wear properties, the organosilica was mixed with polymers.
The resulting composite coatings are characterized by FE-SEM, AFM,
and contact angle measurements. Depending on the nature of the polymer,
different functionalities can be developed. Poly(methyl methacrylate)
leads to almost superhydrophobic and highly transparent coatings.
Composites based on commercial acrylic car paint show “pearl-bouncing”
droplet behavior. A light-emitting polyfluorene is synthesized to
prepare luminescent and water repellent coatings on different supports.
The interactions between polymers and the organosilica influence coating
roughness and are critical for wetting behavior. In summary, the feasibility
of a facile, rapid, and fluorine-free hydrophobization concept was
successfully demonstrated in multipurpose antiwetting applications
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