Surface relief structures on azo polymer films

Viswanathan, Nirmal K.; Kim, Dong Yu; Bian, Shaoping; Williams, John; Liu, Wei; Li, Lian; Samuelson, Lynne A.; Kumar, Jayant; Tripathy, Sukant K.

doi:10.1039/a902424g

Cited by 710 publications

(685 citation statements)

References 77 publications

Supporting

Mentioning

647

Contrasting

Unclassified

Order By: Relevance

“…S4). Azo-bridged polymeric materials are also widely studied 37 for their optical storage applications. As optically stored information is only stable below glass transition temperature (T g ), a high T g means more potential in optical data storage.…”

Section: Synthesismentioning

confidence: 99%

Unprecedented high-temperature CO2 selectivity in N2-phobic nanoporous covalent organic polymers

et al. 2013

View full text Add to dashboard Cite

Post-combustion CO 2 capture and air separation are integral parts of the energy industry, although the available technologies remain inefficient, resulting in costly energy penalties. Here we report azo-bridged, nitrogen-rich, aromatic, water stable, nanoporous covalent organic polymers, which can be synthesized by catalyst-free direct coupling of aromatic nitro and amine moieties under basic conditions. Unlike other porous materials, azo-covalent organic polymers exhibit an unprecedented increase in CO 2 /N 2 selectivity with increasing temperature, reaching the highest value (288 at 323 K) reported to date. Here we observe that azo groups reject N 2 , thus making the framework N 2 -phobic. Monte Carlo simulations suggest that the origin of the N 2 phobicity of the azo-group is the entropic loss of N 2 gas molecules upon binding, although the adsorption is enthalpically favourable. Any gas separations that require the efficient exclusion of N 2 gas would do well to employ azo units in the sorbent chemistry.

show abstract

Section: Synthesismentioning

confidence: 99%

Unprecedented high-temperature CO2 selectivity in N2-phobic nanoporous covalent organic polymers

et al. 2013

View full text Add to dashboard Cite

show abstract

“…In addition, SRGs can be erased using uniform light or heating above T g 11 and then reconstructed, suggesting possible applications such as for active optical devices and memories. 6,9,[12][13][14] However, this method also has a significant disadvantage: its use of azobenzene compounds as optical elements. Such use is undesirable because both the trans and cis isomers of push-pull-type azobenzene compounds, which are typically used to form SRG materials, have strong absorption bands in the vis region.…”

Section: Introductionmentioning

confidence: 99%

“…3,4 Among existing patterning methods, the photoinduced surface relief grating (SRG) formation on films containing azobenzene chromophore is both attractive and novel, as documented in a recent book 5 and reviews. [6][7][8][9][10] The key to SRG formation is thought to be repeatable trans-cis-trans isomerization cycling and reorientation of the azobenzene chromophore upon irradiation with polarized visible (vis) light, typically from the 488-or 514-nm lines of an argon ion laser. SRGs are fabricated by mass transport when an azobenzenecontaining film is irradiated with spatially patterned light at temperatures below the film's glass transition temperature (T g ).…”

Section: Introductionmentioning

confidence: 99%

Facile one-step photopatterning of polystyrene films

Ubukata

Moriya

Yokoyama

2012

Polym J

View full text Add to dashboard Cite

The development of nano-and micropatterned materials is a key component of advanced nanotechnology. We report herein, a photo-based method for patterning general-purpose polymer films. Patterned ultraviolet (UV) light irradiation of a thin polystyrene film under controlled temperature generates surface relief structures by mass transfer from shaded to irradiated areas. The resulting surface relief structure can be arbitrarily erased by heating and reconstructed by patterned UV light irradiation, and this process is repeatable. This new method thus enables fabrication of dynamic reversible patterning structures from various general polymers.

show abstract

“…The competing interpretations are evaluated in Chapter 4, where they are discussed at length. Many reviews of the remarkable body of experimental results are available Delaire and Nakatani, 2000;Yager and Barrett, 2001;Viswanathan et al, 1999).…”

Section: Optical Data Storagementioning

confidence: 99%

“…The resulting materials benefit from the inherent stability, rigidity, and processability of polymers, in addition to the unusual photoresponsive behavior of the azo moieties. Both side-chain and main-chain azobenzene polymers have been prepared (Viswanathan et al, 1999) (Fig. 1.5).…”

Section: Classes Of Azobenzene Systemsmentioning

confidence: 99%