Imprinting Material Research Articles

Advanced nanoimprint lithography using a graded functional imprinting material tailored for liquid crystal alignment

Nanoimprint lithography technology, which is able to easily create nanometer-resolution two-dimensional surface grooves on substrates over a large area by a step and stamp process, opens up an intriguing opportunity for functional liquid crystal (LC) alignment. We describe here a hybrid polymer consisting of two distinct moieties with largely different thermomechanical properties and surface activity. We present the results of nanoimprint lithography experiment using the hybrid polymer to demonstrate the practical applicability as an LC alignment layer. This material shows excellent capability both as a nanoimprinting material, requiring softness at moderate temperatures, and as a LC alignment layer, requiring sufficient rigidity. LC devices using the alignment layer show fairly stable electro-optic characteristics even after thermal aging, due to its high thermal stability. The soft component of the hybrid polymer helps it provide the multiple imprinting capabilities at higher temperatures virtually without any mold damages.

Novel surface ionic imprinting materials prepared via couple grafting of polymer and ionic imprinting on surfaces of silica gel particles

In this paper, a new surface molecular imprinting technique is put forward, and a kind of novel ion-imprinted polymers (IIPs) were prepared through a new approach: firstly functional macromolecule polyethyleneimine (PEI) was grafted onto the surfaces of silica gel particles via the coupling grafting method (“grafting to” method) and the composite material PEI/SiO2 with chemical linking was formed; secondly the ionic imprinting was carried out towards the macromolecule PEI grafted on the surface of silica particles using Cu2+ or Cd2+ ion as a template, epichlorohydrin (ECH) as a crosslinking agent and by coordination linkage actions, and Cu2+ ion (or Cd2+ ion)-imprinted material IIP-PEI/SiO2 was prepared. The binding characteristics of IIP-PEI/SiO2 for Cu2+ ion (or Cd2+ ion) were studied in detail by adopting both static and dynamic methods. The experimental results show that the ion-imprinting material IIP-PEI/SiO2 has specific recognition ability for the template ions, and this character displays mainly in two aspects: (1) it has high affinity for the template ions, its binding amounts for the template ions are much greater than that of the non-imprinted composite material PEI/SiO2, and the adsorption capacity enhances nearly two times compared to PEI/SiO2; (2) it has excellent selectivity for the template ions, for the IIP-PEI/SiO2 by using Cu2+ as template ion, its selectivity coefficients relative to Zn2+ and Ni2+ are 80.21 and 86.08, respectively, and for the IIP-PEI/SiO2 by using Cd2+ as template ion, its selectivity coefficients relative to Cr3+ and Pb2+ are 77.05 and 88.22, respectively. Besides, the imprinting material IIP-PEI/SiO2 has a fine elution property using HCl solution as eluent. The obtained imprinting material by using the new surface molecular imprinting techniques possesses superexcellent binding property for template molecules or ions because of the distribution of imprinted cavities in a thin polymer layer and smaller diffusion barrier.

Synthesis of LaCe-based bulk metallic glasses with low glass transition temperature

LaCe-based bulk metallic glasses (BMGs) with diameter up to 10 mm have been synthesized in copper mold. The BMG alloys have low glass transition temperatures, about 403 K and large supercooled liquid regions up to 58 K. The hardness of the BMG alloys is around 1.9 GPa. They also exhibit large plasticity and imprintability feature in the supercooled liquid region, which make the alloy a potential imprinting material. In addition, the BMG alloys might offer an ideal model system for the study of glass transition with a large experimentally accessible time and low temperature windows.

Low adhesive force of fluorinated sol–gel hybrid materials for easy de-moulding in aUV-based nano-imprint process

A fluorinated methacryl hybrid material, with low surface tension, was used as animprinting material for easy de-moulding in a UV-based nano-imprint process.Specifically, a method to measure the adhesive force between the poly(dimethylsiloxane)(PDMS) mould and the imprinting material, using the force–distance curve ofPDMS, was suggested to represent the de-mouldability of the PDMS mould ina UV-based nano-imprint process. The fluorinated methacryl hybrid materialexhibited a low adhesive force to PDMS, as well as low surface tension, and could benano-imprinted without using an anti-sticking treatment on the PDMS mould.

Use of an Aromatic Polyimide as a Non-Cross-Linked Molecular Imprinting Material

Use of an Aromatic Polyimide as a Non-Cross-Linked Molecular Imprinting Material

CHARACTERIZATION OF ELECTROSYNTHESIZED POLY- (o-AMINOPHENOL) AS A MOLECULAR IMPRINTING MATERIAL FOR SENSOR PREPARATION BY MEANS OF QUARTZ CRYSTAL IMPEDANCE ANALYSIS

ABSTRACT The preparation and properties of electrosynthesized poly-(o-aminophenol) (iPoAP) as a molecular imprinting material were studied by in situ quartz crystal impedance method. During the polymerization, the changes of Δf 0, ΔR 1 and ΔC 0 were investigated based on the Butterworth-Van Dyke model. The thickness shear mode acoustic sensor modified with this material exhibited molecular recognition ability to the template molecule of 2,4-dichlorophenoxyacetic acid, although the specificity was not as good as that of the molecularly imprinted polymer prepared by traditional imprinting technology. In the range of 4.0 × 10−5 to 2.0 × 10−3 M, a linear relationship between the frequency shift (−Δf 0) and log C was found from calibration curve. The determination limit was 1.0 × 10−5 M. Using this electropolymerization technology, the preparation of sensor was very simple and the reproducibility of preparation was very good.

Development of a thickness shear mode acoustic sensor based on an electrosynthesized molecularly imprinted polymer using an underivatized amino acid as the template.

The preparation and characterization of electrosynthesized poly(o-phenylenediamine) (iPoPD) as a molecular imprinting material were studied by an in situ quartz crystal impedance method. The changes of delta f0, delta R1, delta L1 and delta C0 suggest that the polymer film was compact and rigid. The thickness shear mode (TSM) acoustic sensor modified with this material exhibits molecular recognition ability to the template molecule of DL-phenylalanine. In the range 2-20 mM, a linear relationship between the frequency shift delta f0 and logC was found from the calibration graph. Scatchard analysis of the relevant calibration graph offers information on the equilibrium of the binding interaction and the recognition sites. Using this electropolymerization technology, the preparation of the sensor was very simple and the reproducibility of preparation was very good. In particular, it offers possibilities for sensor miniaturization.

Generation of porosity in a hybrid organic-inorganic xerogel by chemical treatment

A hybrid xerogel of 1,4-bis(trimethoxysilylethynyl)benzene was prepared by using a sol-gel process. Chemical treatment of this material was performed under mild conditions in order to remove the organic group using fluoride anion as a catalyst. Experimental procedures were carried out using different solvents, acidities and counter-cations in order to modify the nucleophilic power of F-. Characterization of the residues was done by elemental analysis, spectroscopy (29Si NMR), thermal analysis, pycnometry, surface area measurement and SAXS. The efficiency of the chemical treatment is related to the solvation of the F- anion. It was possible to demonstrate that elimination of the organic part occurs at the same time as a reorganization of the silica network. This reorganization is the result of two competitive F--catalyzed chemical reactions: a redistribution and a polycondensation process known in solution and which take place in the solid. These processes account for the textural characteristics of the final material and may efface the organization of the organic spacers in the hybrid xerogel. These results demonstrate the limitations of silica as a molecular imprinting material and open a new approach to porous silica with adjustable pore size.

A New Imprinting Material for Scanning Electron Microscopic Studies

A new imprinting material, "Thermocool", has been used for preparing negative replicas of plant as well as metal surfaces for SEM study. The technique has wide application and gives very good results.