Patterning Inorganic (CaCO3) Thin Films via a Polymer-Induced Liquid-Precursor Process

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• 作者：Yi-Yeoun Kim ; Elliot P. Douglas ; Laurie B. Gower
• 刊名：Langmuir
• 出版年：2007
• 出版时间：April 24, 2007
• 年：2007
• 卷：23
• 期：9
• 页码：4862 - 4870
• 全文大小：15544K
• 年卷期：v.23,no.9(April 24, 2007)
• ISSN：1520-5827

文摘

The biomimetic synthesis of patterned mineral thin films, based on a combination of the microcontact printingtechnique and a novel crystallization process called the polymer-induced liquid-precursor (PILP) process, is demonstrated.The PILP process enables the deposition of smooth and continuous calcitic mineral films (up to 1500 nm in thickness)under low-temperature and aqueous-based processing conditions. The films are formed by deposition of colloidaldroplets composed of a liquid-phase mineral precursor that is induced by a polymeric process-directing agent (polyaspartateor polyacrylate salts). The droplets can be preferentially deposited onto patterned substrates templated with self-assembled monolayers (SAMs) of alkanethiolate on gold. The droplets coalesce to form an amorphous mineral film,which then transforms (solidifies and crystallizes) while retaining the shape of the patterned template, providing ameans for patterning the location and morphology of two-dimensional calcite crystals. A vertical substrate experimentsupports the premise that the calcite films are created by adsorption of colloidal droplets from solution, rather thanheterogeneous nucleation and growth of an amorphous phase on the SAMs. Large single-crystalline domains, on theorder of 50-100 m, can be "molded" into nonequilibrium morphologies by constraining the mineral precursor toa chemically defined "compartment". Biominerals are well recognized for their elaborate nonequilibrium moldedcrystal morphologies, and increasing evidence suggests that many biominerals are formed from an amorphous precursorthat is stabilized by polyanionic proteins. The biomimetic system examined here, which consists of a polyanionicprocess-directing agent in combination with a functionalized organic template, offers a practical tool for generatingcomplex inorganic structures such as those found in biominerals.