Impact of molecular mass on the elastic modulus of thin polystyrene films

Jessica M. Torres, Christopher M. Stafford, Bryan Vogt

Research output: Contribution to journalArticle

53 Citations (Scopus)

Abstract

Surface wrinkling was used to determine the elastic modulus at ambient temperature of polystyrene (PS) films of varying thickness and relative molecular mass (Mn). A range of Mn from 1.2 kg/mol to 990 kg/mol was examined to determine if the molecular size impacts the mechanical properties at the nanoscale. Ultrathin films exhibited a decrease in modulus for all molecular masses studied here compared to the bulk value. For Mn > 3.2 kg/mol, the fractional change in modulus was statistically independent of molecular mass and the modulus began to deviate from the bulk as the thickness is decreased below ≈50 nm. An order of magnitude decrease in the elastic modulus was found when the film thickness was ≈15 nm, irrespective of Mn. However, an increase in the length scale for nanoconfinement was observed as the molecular mass was decreased below this threshold. The modulus of thin PS films with a molecular mass of 1.2 kg/mol deviated from bulk behavior when the film thickness was decreased below ≈100 nm. This result illustrates that the modulus of thin PS films does not scale with molecular size. Rather, the quench depth into the glass appears to correlate well with the length scale at which the modulus of the films deviates from the bulk, in agreement with molecular simulations from de Pablo and coworkers [31] and recent experimental work [35].

Original languageEnglish (US)
Pages (from-to)4211-4217
Number of pages7
JournalPolymer
Volume51
Issue number18
DOIs
StatePublished - Jan 1 2010

Fingerprint

Polystyrenes
Molecular mass
Elastic moduli
Film thickness
Ultrathin films
Glass
Mechanical properties
Temperature

All Science Journal Classification (ASJC) codes

  • Organic Chemistry
  • Polymers and Plastics
  • Materials Chemistry

Cite this

Torres, Jessica M. ; Stafford, Christopher M. ; Vogt, Bryan. / Impact of molecular mass on the elastic modulus of thin polystyrene films. In: Polymer. 2010 ; Vol. 51, No. 18. pp. 4211-4217.
@article{1c9d61323bab4fbb9a276b14a453b9e9,
title = "Impact of molecular mass on the elastic modulus of thin polystyrene films",
abstract = "Surface wrinkling was used to determine the elastic modulus at ambient temperature of polystyrene (PS) films of varying thickness and relative molecular mass (Mn). A range of Mn from 1.2 kg/mol to 990 kg/mol was examined to determine if the molecular size impacts the mechanical properties at the nanoscale. Ultrathin films exhibited a decrease in modulus for all molecular masses studied here compared to the bulk value. For Mn > 3.2 kg/mol, the fractional change in modulus was statistically independent of molecular mass and the modulus began to deviate from the bulk as the thickness is decreased below ≈50 nm. An order of magnitude decrease in the elastic modulus was found when the film thickness was ≈15 nm, irrespective of Mn. However, an increase in the length scale for nanoconfinement was observed as the molecular mass was decreased below this threshold. The modulus of thin PS films with a molecular mass of 1.2 kg/mol deviated from bulk behavior when the film thickness was decreased below ≈100 nm. This result illustrates that the modulus of thin PS films does not scale with molecular size. Rather, the quench depth into the glass appears to correlate well with the length scale at which the modulus of the films deviates from the bulk, in agreement with molecular simulations from de Pablo and coworkers [31] and recent experimental work [35].",
author = "Torres, {Jessica M.} and Stafford, {Christopher M.} and Bryan Vogt",
year = "2010",
month = "1",
day = "1",
doi = "10.1016/j.polymer.2010.07.003",
language = "English (US)",
volume = "51",
pages = "4211--4217",
journal = "Polymer",
issn = "0032-3861",
publisher = "Elsevier BV",
number = "18",

}

Impact of molecular mass on the elastic modulus of thin polystyrene films. / Torres, Jessica M.; Stafford, Christopher M.; Vogt, Bryan.

In: Polymer, Vol. 51, No. 18, 01.01.2010, p. 4211-4217.

Research output: Contribution to journalArticle

TY - JOUR

T1 - Impact of molecular mass on the elastic modulus of thin polystyrene films

AU - Torres, Jessica M.

AU - Stafford, Christopher M.

AU - Vogt, Bryan

PY - 2010/1/1

Y1 - 2010/1/1

N2 - Surface wrinkling was used to determine the elastic modulus at ambient temperature of polystyrene (PS) films of varying thickness and relative molecular mass (Mn). A range of Mn from 1.2 kg/mol to 990 kg/mol was examined to determine if the molecular size impacts the mechanical properties at the nanoscale. Ultrathin films exhibited a decrease in modulus for all molecular masses studied here compared to the bulk value. For Mn > 3.2 kg/mol, the fractional change in modulus was statistically independent of molecular mass and the modulus began to deviate from the bulk as the thickness is decreased below ≈50 nm. An order of magnitude decrease in the elastic modulus was found when the film thickness was ≈15 nm, irrespective of Mn. However, an increase in the length scale for nanoconfinement was observed as the molecular mass was decreased below this threshold. The modulus of thin PS films with a molecular mass of 1.2 kg/mol deviated from bulk behavior when the film thickness was decreased below ≈100 nm. This result illustrates that the modulus of thin PS films does not scale with molecular size. Rather, the quench depth into the glass appears to correlate well with the length scale at which the modulus of the films deviates from the bulk, in agreement with molecular simulations from de Pablo and coworkers [31] and recent experimental work [35].

AB - Surface wrinkling was used to determine the elastic modulus at ambient temperature of polystyrene (PS) films of varying thickness and relative molecular mass (Mn). A range of Mn from 1.2 kg/mol to 990 kg/mol was examined to determine if the molecular size impacts the mechanical properties at the nanoscale. Ultrathin films exhibited a decrease in modulus for all molecular masses studied here compared to the bulk value. For Mn > 3.2 kg/mol, the fractional change in modulus was statistically independent of molecular mass and the modulus began to deviate from the bulk as the thickness is decreased below ≈50 nm. An order of magnitude decrease in the elastic modulus was found when the film thickness was ≈15 nm, irrespective of Mn. However, an increase in the length scale for nanoconfinement was observed as the molecular mass was decreased below this threshold. The modulus of thin PS films with a molecular mass of 1.2 kg/mol deviated from bulk behavior when the film thickness was decreased below ≈100 nm. This result illustrates that the modulus of thin PS films does not scale with molecular size. Rather, the quench depth into the glass appears to correlate well with the length scale at which the modulus of the films deviates from the bulk, in agreement with molecular simulations from de Pablo and coworkers [31] and recent experimental work [35].

UR - http://www.scopus.com/inward/record.url?scp=77955555442&partnerID=8YFLogxK

UR - http://www.scopus.com/inward/citedby.url?scp=77955555442&partnerID=8YFLogxK

U2 - 10.1016/j.polymer.2010.07.003

DO - 10.1016/j.polymer.2010.07.003

M3 - Article

AN - SCOPUS:77955555442

VL - 51

SP - 4211

EP - 4217

JO - Polymer

JF - Polymer

SN - 0032-3861

IS - 18

ER -