Motornov Mikhail, Sheparovych Roman, Lupitskyy Robert, MacWilliams Emily, Minko Sergiy
Department of Chemistry & Biomolecular Science, Clarkson University, 8 Clarkson Ave., Potsdam, NY 13699-5810, USA.
J Colloid Interface Sci. 2007 Jun 15;310(2):481-8. doi: 10.1016/j.jcis.2007.01.052. Epub 2007 Mar 1.
We report on a method of fabricating stimuli-responsive core-shell nanoparticles using block copolymers covalently bound to a silica nanoparticle surface. We used the "grafting to" approach to graft amphiphilic block copolymer brushes of poly(styrene-b-2-vinylpyridine-b-ethylene oxide) and poly(styrene-b-4-vinylpyridine) onto silica nanoparticles with two different diameters: colloidal silica 200 nm in diameter and fumed silica 15 nm in diameter. We used the pH-responsive properties of the grafted brush to regulate the interactions between the particles, and between the particles and their environment. We show that this behavior can be applied for a reversible formation of particle aggregates, and can be used to tune and stabilize the secondary aggregates of particles of the appropriate size and morphology in an aqueous environment. The suspensions of the particles form a textured hydrophilic coating on various substrates upon casting and the evaporation of water. Heating above the polymer's glass transition temperature or treatment in acidic water result in back and forth switching between superhydrophobic and hydrophilic surfaces, respectively.
我们报道了一种使用共价连接到二氧化硅纳米颗粒表面的嵌段共聚物制备刺激响应性核壳纳米颗粒的方法。我们采用“接枝到”方法，将聚（苯乙烯-b-2-乙烯基吡啶-b-环氧乙烷）和聚（苯乙烯-b-4-乙烯基吡啶）的两亲性嵌段共聚物刷接枝到两种不同直径的二氧化硅纳米颗粒上：直径为200 nm的胶体二氧化硅和直径为15 nm的气相二氧化硅。我们利用接枝刷的pH响应特性来调节颗粒之间以及颗粒与其环境之间的相互作用。我们表明，这种行为可用于颗粒聚集体的可逆形成，并可用于在水性环境中调节和稳定具有适当尺寸和形态的颗粒的二次聚集体。颗粒悬浮液在浇铸和水蒸发后会在各种基材上形成有纹理的亲水性涂层。加热至聚合物的玻璃化转变温度以上或在酸性水中处理分别会导致超疏水和亲水表面之间的来回切换。
