A direct-write "dip-pen" nanolithography (DPN) has been developed to deliver collections of molecules in a positive printing mode. An atomic force microscope (AFM) tip is used to write alkanethiols with 30-nanometer linewidth resolution on a gold thin film in a manner analogous to that of a dip pen. Molecules are delivered from the AFM tip to a solid substrate of interest via capillary transpor...

Methods for functionalizing micrometer-sized colloidal spheres with three or more zones of chemical functionality (ABA or ABC) are described. To produce ABA triblock colloids, we functionalized the north pole, south pole, and equator to produce what we call X, Y, and K functionality according to the number of allowed nearest neighbors and their spatial arrangements. These synthesis methods allo...

The detection of multiple targets in a single sample is important for many applications, including medical diagnostics, genotyping, and drug discovery. The current approaches to multiplexing, such as planar arrays (such as DNA microarrays) and suspension (particle-based) arrays, require expensive or cumbersome means of encoding, decoding, or functionalizing substrates. Currently, commercially a...

CO(2)-switchable gold nanoparticles (AuNPs) were prepared by functionalizing AuNPs with CO(2)-switchable polymers. Their dispersion-re-dispersion in and separation from aqueous solution can be easily and reproducibly adjusted by CO(2) bubbling through and removal from the solution, enabling unique CO(2) controllable, efficient in situ recycling of NPs. As compared to non-functionalized AuNPs, t...

pH-responsive surfaces, reversibly switching between superhydrophilicity and superhydrophobicity/water repellency, are developed by "grafting from" a pH-sensitive polymer onto a hierarchically micro/nano-structured substrate. We quantify the water repellency by investigating the restitution coefficient of water droplets bouncing off the surfaces. The water repellent state requires appropriate h...

This reaserch aims at functionalizing magnetic mesoporous silica with methacrylic acid-3-aminopropyltriethoxysilane (Fe3O4@MCM-41@MAA-APTES) applied for removal of methylene blue from aqueous solution. Several variables (such as pH, dye concentration, adsorbent amount and contact time) have been investigated. Under optimum conditions, maximum capacity of 87.71 mg g-1 of MB was obtained for the ...