Polydiacetylene Macromolecules in Solution: Rods, Coils and Gels

Lim, K. C.; Kapitulnik, A.; Zacher, Robert A.; Casalnuovo, S.A.; Wudl, Fred; Heeger, A. J.

doi:10.1007/978-94-017-2713-6_20

Cited by 5 publications

(3 citation statements)

References 12 publications

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“…15 Thus one might expect that this would add about 22 nm to the calculated linewidths. Swelling in the developer does not account for the magnitude of the feature.…”

Section: Discussionmentioning

confidence: 97%

Lithography with a 50 KV e beam and a vacuum scanning tunneling microscope in a polydiacetylene negative resist

Dobisz¹

1990

Journal of Vacuum Science &Amp; Technology B: Microelectronics Processing and Phenomena

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High resolution electron beam lithography with a polydiacetylene negative resist at 50 kVWe present complementary studies of high (50 KeV) and low (5 eV) energy e-beam lithography in a polydiacetylene negative resist. A 50 KV probe of lie radius 8.3 nm defined a minimum continuous linewidth of ;::: 80 mn, with a dose of 1. 7 nC/cm. The scanning tunneling microscope (STM) can image and lithographically pattern the resist in situ. Comparison of STM images of undeveloped lines to micrographs of developed lines show little difference in size. Lines, 55 nm wide, were produced by a 5 V probe with a line dose of 20 Il-C/cm. The latent images of the 5 V defined lines and the 50 KV defined lines both appear as depressions in the resist. The minimum feature sizes cannot be explained by the probe diameters, electron scattering, or resist swelling in the developer, The possible effect of resist chemistry on the minimum feature size is discussed.

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“…15 Thus one might expect that this would add about 22 nm to the calculated linewidths. Swelling in the developer does not account for the magnitude of the feature.…”

Section: Discussionmentioning

confidence: 97%

Lithography with a 50 KV e beam and a vacuum scanning tunneling microscope in a polydiacetylene negative resist

Dobisz¹

1990

Journal of Vacuum Science &Amp; Technology B: Microelectronics Processing and Phenomena

View full text Add to dashboard Cite

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“…The backbone structures of π-conjugated polymers differ dramatically from those of polymers with saturated backbones. These polymeric semiconductors are generally composed of a backbone consisting of aromatic and/or heteroaromatic rings bonded to one another. , Charge transport in these conjugated structures is enabled by delocalization between overlapping π-orbitals, − which gives rise to the band structure . Electronic delocalization is generally energetically favorable, resulting in highly planar polymer chains. − The semiconducting behavior of these π-conjugated materials in particular has given rise to a myriad of device applications, from organic transistors and solar cells to chemical sensors .…”

Section: Introductionmentioning

confidence: 99%

“…These polymeric semiconductors are generally composed of a backbone consisting of aromatic and/or heteroaromatic rings bonded to one another. 1,2 Charge transport in these conjugated structures is enabled by delocalization between overlapping π-orbitals, 3−5 which gives rise to the band structure. 6 Electronic delocalization is generally energetically favorable, resulting in highly planar polymer chains.…”

Section: ■ Introductionmentioning

confidence: 99%

Decoupling Planarizing and Steric Energetics to Accurately Model the Rigidity of π-Conjugated Polymers

et al. 2023

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The π-conjugated backbone of semiconducting polymers gives rise to both their electronic properties and structural rigidity. However, current computational methods for understanding the rigidity of polymer chains fail in one crucial way. Namely, standard torsional scan (TS) methods do not satisfactorily capture the behavior of polymers exhibiting a high degree of steric hindrance. This deficiency in part stems from the method by which torsional scans decouple energy related to electron delocalization from that related to nonbonded interactions. These methods do so by applying classical corrections of the nonbonded energy to the quantum mechanical (QM) torsional profile for polymers that are highly sterically hindered. These large corrections to the energy from nonbonded interactions can substantially skew the calculated QM energies related to torsion, resulting in an inaccurate or imprecise estimation of the rigidity of a polymer. As a consequence, simulations of the morphology of a highly sterically hindered polymer using the TS method can be highly inaccurate. Here, we describe an alternative, generalizable method by which the delocalization energy can be decoupled from the energy associated with nonbonded interactions�the "isolation of delocalization energy" (DE) method. From torsional energy calculations, we find that the relative accuracy of the DE method is similar to the TS method (within 1 kJ/mol) for two model polymers (P3HT, PTB7) when compared to quantum mechanical calculations. However, the DE method significantly increased the relative accuracy for simulations of PNDI-T, a highly sterically hindered polymer (8.16 kJ/mol). Likewise, we show that comparison of the planarization energy (i.e., backbone rigidity) from torsional parameters is significantly more precise for both PTB7 and PNDI-T when using the DE method as opposed to the TS method. These differences affect the simulated morphology, with the DE method predicting a significantly more planar configuration of PNDI-T.

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