19 research outputs found
The Renaissance, The Reformation and The Rise of Science. By Harold P. Nebelsick. Edinburgh, T. & T. Clark, 1992. Pp. xxi + 237. £16.95.
The Ministry of the Elders in the Reformed Church: Papers Presented at a Consultation Held in Geneva in August 1990, Veroffentlichung, Nr. 5. Edited by Lukas Vischer. Berne, Evangelische Arbeitsstelle Oekumene Schweiz, 1992. Pp. 258. No price.
Theories of Culture: A New Agenda for Theology. By Kathryn Tanner. Minneapolis: Fortress Press, 1997. 196 pages. $13.00.
Bunyan the Christian. By Gordon Wakefield. London, Harper Collins Religious, 1992. Pp. x + 143. £17.95.
Mutuality and difference: trinity, creation and the theological ground of the church's unity
The ‘True Remedy’: Jonathan Edwards' Soteriological Perspective as Observed in his Revival Treatises
Parameters Affecting Interfacial Assembly and Alignment of Nanotubes
Tangential flow interfacial self-assembly (TaFISA) is
a promising
scalable technique enabling uniformly aligned carbon nanotubes for
high-performance semiconductor electronics. In this process, flow
is utilized to induce global alignment in two-dimensional nematic
carbon nanotube assemblies trapped at a liquid/liquid interface, and
these assemblies are subsequently deposited on target substrates.
Here, we present an observational study of experimental parameters
that affect the interfacial assembly and subsequent aligned nanotube
deposition. We specifically study the water contact angle (WCA) of
the substrate, nanotube ink composition, and water subphase and examine
their effects on liquid crystal defects, overall and local alignment,
and nanotube bunching or crowding. By varying the substrate chemical
functionalization, we determine that highly aligned, densely packed,
individualized nanotubes deposit only at relatively small WCA between
35 and 65°. At WCA (< 10°), high nanotube bunching or
crowding occurs, and the film is nonuniform, while aligned deposition
ceases to occur at higher WCA (>65°). We find that the best
alignment,
with minimal liquid crystal defects, occurs when the polymer-wrapped
nanotubes are dispersed in chloroform at a low (0.6:1) wrapper polymer
to nanotube ratio. We also demonstrate that modifying the water subphase
through the addition of glycerol not only improves overall alignment
and reduces liquid crystal defects but also increases local nanotube
bunching. These observations provide important guidance for the implementation
of TaFISA and its use toward creating technologies based on aligned
semiconducting carbon nanotubes
Boundary-directed epitaxy of block copolymers
Directing the position, orientation, and long-range lateral order of block copolymer domains to produce technologically-useful, sublithographic patterns is a challenge. Here, the authors present a promising approach to overcome the challenge by directing assembly using spatial boundaries between planar, low-resolution regions on a surface with different composition
Nanotube Alignment Mechanism in Floating Evaporative Self-Assembly
The
challenge of assembling semiconducting single-wall carbon nanotubes
(s-SWCNTs) into densely packed, aligned arrays has limited the scalability
and practicality of high-performance nanotube-based electronics technologies.
The aligned deposition of s-SWCNTs via floating evaporative self-assembly
(FESA) has promise for overcoming this challenge; however, the mechanisms
behind FESA need to be elucidated before the technique can be improved
and scaled. Here, we gain a deeper understanding of the FESA process
by studying a stationary analogue of FESA and optically tracking the
dynamics of the organic ink/water/substrate and ink/air/substrate
interfaces during the typical FESA process. We observe that the ink/water
interface serves to collect and confine the s-SWCNTs before alignment
and that the deposition of aligned bands of s-SWCNTs occurs at the
ink/water/substrate contact line during the depinning of both the
ink/air/substrate and ink/water/substrate contact lines. We also demonstrate
improved control over the interband spacing, bandwidth, and packing
density of FESA-aligned s-SWCNT arrays. The substrate lift rate (5–15
mm min<sup>–1</sup>) is used to tailor the interband spacing
from 90 to 280 μm while maintaining a constant aligned s-SWCNT
bandwidth of 50 μm. Varying the s-SWCNT ink concentration (0.75–10
μg mL<sup>–1</sup>) allows the control of the bandwidth
from 2.5 to 45 μm. A steep increase in packing density is observed
from 11 s-SWCNTs μm<sup>–1</sup> at 0.75 μg mL<sup>–1</sup> to 20 s-SWCNTs μm<sup>–1</sup> at 2
μg mL<sup>–1</sup>, with a saturated packing density
of ∼24 s-SWCNTs μm<sup>–1</sup>. We also demonstrate
the scaling of FESA to align s-SWCNTs on a 2.5 × 2.5 cm<sup>2</sup> scale while preserving high-quality alignment on the nanometer scale.
These findings help realize the scalable fabrication of well-aligned
s-SWCNT arrays to serve as large-area platforms for next-generation
semiconductor electronics