Multipurpose Ultra and Superhydrophobic Surfaces Based on Oligodimethylsiloxane-Modified Nanosilica Raquel de Francisco, † Pilar Tiemblo,* ,† Mario Hoyos, † Camino Gonza ́ lez-Arellano, †,⊥ Nuria García,* ,† Lars Berglund, ‡ and Alla Synytska §,∥ † Instituto de Ciencia y Tecnología de Polímeros, ICTP-CSIC, Juan de la Cierva 3, 28006 Madrid, Spain ‡ Wallenberg Wood Science Center, KTH Royal Institute of Technology, SE-10044 Stockholm, Sweden § Leibniz-Institut fü r Polymerforschung Dresden e.V., Hohe Str. 6, D-01069 Dresden, Germany ∥ Technische Universitä t Dresden, Physical Chemistry of Polymer Materials, 01062 Dresden, Germany * S Supporting Information ABSTRACT: 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. KEYWORDS: superhydrophobic, coating, organosilica, oligodimethylsiloxane 1. INTRODUCTION During the past decade, superhydrophobic surfaces have received much attention because of the challenge of under- standing their basis 1−3 and the many technological implications they possess. Self-cleaning, antiicing, superslippery or anti- biofouling surfaces can be developed from the same concept. 4−7 Most of the applications require coatings for large surfaces. This is a difficulty, since many strategies followed to hydrophobize surfaces are not easily applicable to large surface areas. 8 Therefore, a current target is to find suitable concepts for preparation and application of hydrophobic and mechanically stable coatings to large multipurpose areas. Furthermore, optical transparency 9 is an additional feature of great importance in many industrial applications. This property cocktail is an ambitious objective. This is why, in spite of the vast amount of literature devoted to superhydrophobicity, commercially available products are still limited. In particular, the difficulties associated with the surface roughness design are the most complicated to overcome. Superhydrophobicity is based on the combination of low surface energy and suitable topography. Strictly speaking, the definition implies a water contact angle, θ w , higher than 150° and, most importantly, a hysteresis, Δθ, defined as the difference between advancing and receding water contact Received: July 24, 2014 Accepted: October 2, 2014 Published: October 2, 2014 Research Article www.acsami.org © 2014 American Chemical Society 18998 dx.doi.org/10.1021/am504886y | ACS Appl. Mater. Interfaces 2014, 6, 18998−19010