A Simple Method for Spin‐Coating Molecularly Imprinted Polymer Films of Controlled Thickness and Porosity

Abstract

sample compartment containing an integrating sphere. For precise comparisons, both solution and solid-state absolute quantum yield of luminescence efficiencies (±10 %) were obtained using an integrating sphere, as previously reported [13]. The excitation wavelength was 320 nm for all polymers, except PFT-A (409 nm). Solutions were deoxygenated with highly pre-purified nitrogen prior to the fluorescence measurements and the sample compartment was flushed with nitrogen for thin film measurements. Fluorescent spectra of the thin films, spin cast from CHCl 3 on quartz, had an optical density of~0.5. Spectra were recorded 22.5 normal to the incident light. [1] The general approach involves attaching the MIP onto the surface of a transducer that senses binding events between the MIP and the target analyte and sends a quantifiable signal to the user. This usually requires an MIP that has been prepared in a film format, and it is often necessary to control the thickness and porosity of the film in order to optimize the sensitivity of the device. Until now, the in situ synthesis of films, via the polymerization of vinyl-based monomers (i.e., how the vast majority of MIPs are prepared), has relied on awkward adaptations of bulk-polymerization techniques, resulting in poor control of film thickness and porosity, [2] or on the use of somewhat cumbersome surface-initiated polymerization methods. [3] Due to the physical properties of traditional imprinting mixtures (e.g., high volatility and, for some cases, excessively low viscosity), spin-coating and many other standard coating techniques have not been applied at all. [2] This communication addresses this problem by introducing a simple, quick, and robust technique for preparing MIP films. Spin-coating was used to spread a MIP pre-polymerization mixture onto a substrate, and UV photolysis was used to cure the films. A novel porogenic system, which consists of a low-volatility solvent and soluble, linear polymers, is a critical feature of this process. Both the porosity and the capacity of the imprinted films were greatly enhanced in the presence of the polymer porogen. Using a chiral template, we demonstrate that the selectivity of the MIP films produced by this method is compar-COMMUNICATIONS Received

Hierarchically Nanostructured Polymer Films Based on Molecularly Imprinted Surface‐Bound Nanofilaments

“…Therefore access by diffusion to the binding sites buried inside the material was very slow or impossible, resulting in a very low binding capacity of the films. [10,17] As demonstrated in the present work, the use of nanostructured surfaces with a high aspect ratio is a remedy for this problem. In order to demonstrate that nanostructuring of the molecularly imprinted surface not only increases surface area and accessibility of the binding sites but also allows fine-tuning the surface properties, we have studied the formation of water microdroplets at the surface at a microscale level by environmental scanning electron microscopy (ESEM).…”

“…Several approaches have been proposed to in-situ generate MIP films, such as, electropolymerization, [6,7] the use of surface-bound initiators, [8] or classic coating techniques like spin-coating. [9,10] In the present work, we describe the preparation of nanostructured molecularly imprinted surfaces with a high aspect ratio using nanomolding on a porous template surface. We have used porous alumina as a sacrificial nanoporous template material, although in principle other nanostructured templates can be used.…”

Electrosynthesized molecularly imprinted polymers for protein recognition

“…Adherent MIP films can be polymerized in-situ by free-radical polymerization for example by spin coating [39] or drop-casting the pre-polymerization mixture onto the substrate and inducing polymerization [40]. Better control over the thickness of the sensing layer can be achieved with surface confined polymerization methods, where either the initiator [41,42] or a pendant polymerizable group [43] is attached to the surface.…”

Surface‐Confined Electropolymerization of Methylene Blue on Gold Electrodes

“…Polymer ultrathin films can be immobilized to different surfaces by using numerous techniques, such as Langmuir-Blodgett technique [4], spin coating [5], self-assembly [6], and electropolymerization [7,8]. There are some problems in the modification of surfaces: poor contact between substrate and polymer film, deficiency in the conjugation of immobilized polymer, and controlling the molecular weight of the conducting polymer [9][10][11].…”