Fully stretched DNA molecules are becoming a fundamental component of new systems for comprehensive genome analysis. Among a number of approaches for elongating DNA molecules, nanofluidic molecular confinement has received enormous attentions from physical and biological communities for the last several years. Here we demonstrate a well-optimized condition that a DNA molecule can stretch almost its full contour length: the average stretch is 19.1 μm ± 1.1 μm for YOYO-1 stained λ DNA (21.8 μm contour length) in 250 nm × 400 nm channel, which is the longest stretch value ever reported in any nanochannels or nanoslits. In addition, based on Odijk’s polymer physics theory, we interpret our experimental findings as a function of channel dimensions and ionic strengths. Furthermore, we develop a Monte Carlo simulation approach using a primitive model for the rigorous understandings of DNA confinement effects. Collectively, we present more complete understanding of nanochannel confined DNA stretching via the comparisons to computer simulation results and Odijk’s polymer physics theory.

Monte Carlo simulations are performed to investigate the role of the divalent cation Ca on the stability and swelling of montmorillonite. Constant stress simulations (NPzzT ensemble) are used to predict the basal spacing as a function of the water content in the interlayer, and constant chemical potential simulations (μVT ensemble) are used to find the more stable basal spacings of the clay–water systems. Two model clays are considered in this work, namely, Otay and Wyoming montmorillonites. It is found that the equilibrium basal spacings for Otay montmorillonite are D1=11.9 Å and D2=14.4 Å. For Wyoming montmorillonite they are D1=12.2 Å and D2=14.7 Å. It is also found that montmorillonites develop one layer of water at D1, and two layers of water at D2. We found that, for all the water contents considered here, the cations are hydrated.

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Dissolution characteristics of a positive chemically amplified photoresist, AZ-PF514 from Hoechst Celanese, have been studied. Development rate monitor data for different developer concentrations are analyzed. The experimental dissolution rates of the X-ray-exposed photoresist are examined in view of the dissolution model proposed earlier by Reiser. Parameters of Reiser's model associated with the diffusion of an aqueous base through a thin penetration layer and solubility of a phenolate complex in an aqueous base solution are derived for different X-ray exposure conditions. Reiser's dissolution model was used to simulate the developed photoresist pattern profile. An example of 0.25 µm pattern development simulation using a dose-dependent coefficient for diffusion of a developer base into polymer is demonstrated.

The classical materials creation process involves a laborious procedure wherein intuition drives the design of a material that is then created, and tested. In most cases, the design goals are not attained, and this costly procedure is repeated. The Materials Genome Initiative (MGI) seeks to replace this process and thus bring innovative new materials into commercial applications faster and at a lesser expense. The Center for Hierarchical Materials Design (CHiMaD) is the NIST-sponsored Center of Excellence for Advanced Materials Research focusing on developing the next generation of computational tools, databases, and experimental techniques in order to enable the accelerated design of novel materials and their integration into industry. To illustrate the potential of the MGI, we are designing a wide range of materials from Co-superalloys to block co-polymers for nanolithography. Each of these design efforts requires databases and simulation. A discussion of the databases, data mining and materials simulation efforts will be given.