This review looks at the efforts that are being made to modify the surface of poly(dimethylsiloxane) (PDMS) microchannels, in order to enhance applicability in the field of microfluidics. Many surface modifications of PDMS have been performed for electrophoretic separations, but new modifications are being done for emerging applications such as heterogeneous immunoassays and cell-based bioassays. These new modification techniques are powerful because they impart biospecificity to the microchannel surfaces and reduce protein adsorption. Most of these applications require the use of aqueous or polar solvents, which makes surface modification a very important topic.

Atomic vacancies with controlled depth and size are generated on a graphite surface by lowenergy ion bombardment. The reactivity of vacancies towards an oxygen molecule is investigated by using scanning tunneling microscopy (STM) and density functional theory. An oxygen molecule (i) exothermally dissociates and then chemisorbs at the top sites and /or the bridge sites of a vacancy, or (ii) forms a precursor state of molecular oxygen at a bridge site. Reaction pathways for oxidative etching are proposed to interpret serpentine and circular etching patterns observed by STM.

Inelastic electron tunneling spectroscopy and microscopy with a scanning tunneling microscope revealed two vibrational modes showing a decrease in conductance at +/-82.0 and +/-38.3 mV sample bias for single oxygen molecules chemisorbed on the fourfold hollow sites of Ag(110) surface at 13 K. The spatial distribution of the vibrational intensities exhibited pi(g)-orbital (perpendicular to surface) symmetry of O2 with the molecular axis along the [001] direction. These results are attributed to resonant inelastic electron tunneling.

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Conductive hydrogels are a class of composite materials that consist of hydrated and conducting polymers. Due to the mechanical similarity to biointerfaces such as human skin, conductive hydrogels have been primarily utilized as bioelectrodes, specifically neuroprosthetic electrodes, in an attempt to replace metallic electrodes by enhancing the mechanical properties and long-term stability of the electrodes within living organisms. Here, we report a conductive, smart hydrogel, which is thermoplastic and self-healing owing to its unique properties of reversible liquefaction and gelation in response to thermal stimuli. In addition, we demonstrated that our conductive hydrogel could be utilized to fabricate bendable, stretchable, and patternable electrodes directly on human skin. The excellent mechanical and thermal properties of our hydrogel make it potentially useful in a variety of biomedical applications such as electronic skin.