Direct Observation of Photoinduced trans-cis Isomerization on Azobenzene Single Crystal

Chia Yun Lai, Gijo Raj, Ieva Liepuoniute, Matteo Chiesa, Pance Naumov

Research output: Contribution to journalArticle

Abstract

Photoexcitation can lead to either homogeneous or heterogeneous transformations of a reactive surface. Homogeneous transformations result in a statistical mixture of reactants and products, whereas the outcome of heterogeneous transformations is a coexistence of macroscopic reactant and product domains, separated by a phase boundary. Heterogeneous photoinduced changes are also typically restricted to the surface, have individual phase structures that are inaccessible with classical diffraction methods, and possess surface properties that cannot readily be measured by the traditional wetting (water contact angle) technique. In this study, we demonstrate application of Atomic Force Microscopy (AFM) to obtain high spatial resolution surface energy distribution in the trans and cis domains on the surface of azobenzene single crystal. UV excitation of single crystals of 3′,4′-dimethyl-4-(dimethylamino)azobenzene results in domino-like trans-to-cis isomerization on their surface. In the AFM phase channel, this affords contrasting domains with different physicochemical properties. Small amplitude small set point (SASS) method and bimodal AFM operated in the attractive regime provide maps of the tip-sample adhesion force and the Hamaker constant, respectively. The results show that the Hamaker constant of the cis domains (∼1 × 10-19 J) is higher than that of the trans domains (∼7 × 10-20 J). After UV irradiation, the calculated surface energies of the domains were ∼40% higher based on the Hamaker constant. Within a broader context, the results presented here demonstrate the potency of AFM-based surface-sensitive techniques for probing of the dynamic changes in surface properties upon photoinduced isomerization of molecular switches.

Original languageEnglish (US)
Pages (from-to)3306-3312
Number of pages7
JournalCrystal Growth and Design
Volume17
Issue number6
DOIs
StatePublished - Jun 7 2017

Fingerprint

Azobenzene
Isomerization
isomerization
Single crystals
Atomic force microscopy
single crystals
atomic force microscopy
Interfacial energy
Surface properties
surface properties
surface energy
Photoexcitation
Phase boundaries
Phase structure
Contact angle
Wetting
products
photoexcitation
Adhesion
Diffraction

ASJC Scopus subject areas

  • Chemistry(all)
  • Materials Science(all)
  • Condensed Matter Physics

Cite this

Direct Observation of Photoinduced trans-cis Isomerization on Azobenzene Single Crystal. / Lai, Chia Yun; Raj, Gijo; Liepuoniute, Ieva; Chiesa, Matteo; Naumov, Pance.

In: Crystal Growth and Design, Vol. 17, No. 6, 07.06.2017, p. 3306-3312.

Research output: Contribution to journalArticle

Lai, Chia Yun ; Raj, Gijo ; Liepuoniute, Ieva ; Chiesa, Matteo ; Naumov, Pance. / Direct Observation of Photoinduced trans-cis Isomerization on Azobenzene Single Crystal. In: Crystal Growth and Design. 2017 ; Vol. 17, No. 6. pp. 3306-3312.
@article{558f6be0394549c4a99960e98534903e,
title = "Direct Observation of Photoinduced trans-cis Isomerization on Azobenzene Single Crystal",
abstract = "Photoexcitation can lead to either homogeneous or heterogeneous transformations of a reactive surface. Homogeneous transformations result in a statistical mixture of reactants and products, whereas the outcome of heterogeneous transformations is a coexistence of macroscopic reactant and product domains, separated by a phase boundary. Heterogeneous photoinduced changes are also typically restricted to the surface, have individual phase structures that are inaccessible with classical diffraction methods, and possess surface properties that cannot readily be measured by the traditional wetting (water contact angle) technique. In this study, we demonstrate application of Atomic Force Microscopy (AFM) to obtain high spatial resolution surface energy distribution in the trans and cis domains on the surface of azobenzene single crystal. UV excitation of single crystals of 3′,4′-dimethyl-4-(dimethylamino)azobenzene results in domino-like trans-to-cis isomerization on their surface. In the AFM phase channel, this affords contrasting domains with different physicochemical properties. Small amplitude small set point (SASS) method and bimodal AFM operated in the attractive regime provide maps of the tip-sample adhesion force and the Hamaker constant, respectively. The results show that the Hamaker constant of the cis domains (∼1 × 10-19 J) is higher than that of the trans domains (∼7 × 10-20 J). After UV irradiation, the calculated surface energies of the domains were ∼40{\%} higher based on the Hamaker constant. Within a broader context, the results presented here demonstrate the potency of AFM-based surface-sensitive techniques for probing of the dynamic changes in surface properties upon photoinduced isomerization of molecular switches.",
author = "Lai, {Chia Yun} and Gijo Raj and Ieva Liepuoniute and Matteo Chiesa and Pance Naumov",
year = "2017",
month = "6",
day = "7",
doi = "10.1021/acs.cgd.7b00288",
language = "English (US)",
volume = "17",
pages = "3306--3312",
journal = "Crystal Growth and Design",
issn = "1528-7483",
publisher = "American Chemical Society",
number = "6",

}

TY - JOUR

T1 - Direct Observation of Photoinduced trans-cis Isomerization on Azobenzene Single Crystal

AU - Lai, Chia Yun

AU - Raj, Gijo

AU - Liepuoniute, Ieva

AU - Chiesa, Matteo

AU - Naumov, Pance

PY - 2017/6/7

Y1 - 2017/6/7

N2 - Photoexcitation can lead to either homogeneous or heterogeneous transformations of a reactive surface. Homogeneous transformations result in a statistical mixture of reactants and products, whereas the outcome of heterogeneous transformations is a coexistence of macroscopic reactant and product domains, separated by a phase boundary. Heterogeneous photoinduced changes are also typically restricted to the surface, have individual phase structures that are inaccessible with classical diffraction methods, and possess surface properties that cannot readily be measured by the traditional wetting (water contact angle) technique. In this study, we demonstrate application of Atomic Force Microscopy (AFM) to obtain high spatial resolution surface energy distribution in the trans and cis domains on the surface of azobenzene single crystal. UV excitation of single crystals of 3′,4′-dimethyl-4-(dimethylamino)azobenzene results in domino-like trans-to-cis isomerization on their surface. In the AFM phase channel, this affords contrasting domains with different physicochemical properties. Small amplitude small set point (SASS) method and bimodal AFM operated in the attractive regime provide maps of the tip-sample adhesion force and the Hamaker constant, respectively. The results show that the Hamaker constant of the cis domains (∼1 × 10-19 J) is higher than that of the trans domains (∼7 × 10-20 J). After UV irradiation, the calculated surface energies of the domains were ∼40% higher based on the Hamaker constant. Within a broader context, the results presented here demonstrate the potency of AFM-based surface-sensitive techniques for probing of the dynamic changes in surface properties upon photoinduced isomerization of molecular switches.

AB - Photoexcitation can lead to either homogeneous or heterogeneous transformations of a reactive surface. Homogeneous transformations result in a statistical mixture of reactants and products, whereas the outcome of heterogeneous transformations is a coexistence of macroscopic reactant and product domains, separated by a phase boundary. Heterogeneous photoinduced changes are also typically restricted to the surface, have individual phase structures that are inaccessible with classical diffraction methods, and possess surface properties that cannot readily be measured by the traditional wetting (water contact angle) technique. In this study, we demonstrate application of Atomic Force Microscopy (AFM) to obtain high spatial resolution surface energy distribution in the trans and cis domains on the surface of azobenzene single crystal. UV excitation of single crystals of 3′,4′-dimethyl-4-(dimethylamino)azobenzene results in domino-like trans-to-cis isomerization on their surface. In the AFM phase channel, this affords contrasting domains with different physicochemical properties. Small amplitude small set point (SASS) method and bimodal AFM operated in the attractive regime provide maps of the tip-sample adhesion force and the Hamaker constant, respectively. The results show that the Hamaker constant of the cis domains (∼1 × 10-19 J) is higher than that of the trans domains (∼7 × 10-20 J). After UV irradiation, the calculated surface energies of the domains were ∼40% higher based on the Hamaker constant. Within a broader context, the results presented here demonstrate the potency of AFM-based surface-sensitive techniques for probing of the dynamic changes in surface properties upon photoinduced isomerization of molecular switches.

UR - http://www.scopus.com/inward/record.url?scp=85020247537&partnerID=8YFLogxK

UR - http://www.scopus.com/inward/citedby.url?scp=85020247537&partnerID=8YFLogxK

U2 - 10.1021/acs.cgd.7b00288

DO - 10.1021/acs.cgd.7b00288

M3 - Article

VL - 17

SP - 3306

EP - 3312

JO - Crystal Growth and Design

JF - Crystal Growth and Design

SN - 1528-7483

IS - 6

ER -