Supramolecular Chemistry for Pressure Sensitive Adhesives ? Gordon - - PowerPoint PPT Presentation

Supramolecular Chemistry for Pressure Sensitive Adhesives ?

Olivier Herscher, Cécile Fonteneau Sandrine Pensec, Laurent Bouteiller LCP, UPMC, Paris, France

Xavier Callies, 3nd year Phd Student

Guylaine Ducouret, Costantino Creton SIMM, ESPCI ParisTech, Paris, France

Gordon Seminar 2014

A material which sticks on almost any surface by simple contact, without chemical reaction

Viscoelastic Materials PSA = Pressure Sensitive Adhesives Liquid Solid

Introduction Bis-Urea PnBA Copolymer & Resins

1 2 σ0

Non flowing

1 2

Dissipative

A material which sticks on almost any surface by simple contact, without chemical reaction

Viscoelastic Materials PSA = Pressure Sensitive Adhesives Liquid Solid Classic Formulation (Acrylic) Low Tg < -40°C

Long entangled polymers Chains For ex, PnBA ≈ -50°C Light cross-linking + Pendant Short Chains

O O

n

Introduction Bis-Urea PnBA Copolymer & Resins

1 2 σ0

Non flowing

1 2

Dissipative

Challenge of our project : Is it possible to get a viscoelastic behavior required for a PSA with unentangled molecules with strong but reversible interactions ? Strongly interacting moieties separated by flexible polymer chains. What is required ?

Introduction Copolymer & Resins Bis-Urea PnBA

New Chemical Parameters High Solubility in Organic Solvent Supramolecular System

Challenge of our project : Is it possible to get a viscoelastic behavior required for a PSA with unentangled molecules with strong but reversible interactions ? Strongly interacting moieties separated by flexible polymer chains. What is required ?

Introduction Copolymer & Resins Bis-Urea PnBA

New Chemical Parameters High Solubility in Organic Solvent Supramolecular System Strategy

Synthesize Supramolecular Model Systems with a highly controlled chemical structure. Systematic Rheological and Adhesive Characterization

N H N H O N H N H O O O Br O O

n

O O Br O O

n

Introduction Bis-Urea PnBA Copolymer & Resins Polar Core Side Chain Side Chain Self-assembly

• f Stickers1

1Pensec et al, Macromolecules, 2010, 43, 2529-2534 1Courtois et al, J. Adv. Funct. Mater,2010, 20, 1803-1811

Model System n°1 Urea Bis-urea Xylene Center-Functionalized PnBA

Introduction Copolymer & Resins Strategy for Synthesis Sticker is the initiator of the polymerization. Growth of two symmetric side chains by ATRP (Ip < 1,4).

Influence of Mw

Bis-Urea PnBA

Mw 5 kg/mol 120 kg/mol Φsticker (w%) 4% 0,2%

10 10

1

10

2

10

3

10

4

10

5

G' & G'' (Pa)

4 5 6

1

2 3 4 5 6

10

2 3

Angular Velocity (rad/s) PnBAX5 PnBAX8 PnBAX20

10 10

1

10

2

10

3

10

4

10

5

G' & G'' (Pa)

4 5 6

1

2 3 4 5 6

10

2 3

Angular Velocity (rad/s) PnBAX40 PnBAX115

Viscoelastic behavior at 25°C (in the melt state)

At a fixed ω, G’ & G’’ ↘ if Mw ↗ At a fixed ω, G’ & G’’ ↗ if Mw ↗ Introduction Copolymer & Resins Bis-Urea PnBA All Viscoelastic Fluids at RT

G’’ G’’ G’’ G’ G’ G’ G’ G’ G’’ G’’

Introduction Copolymer & Resins Bis-Urea PnBA η*=√(G’2+G’’2)/ω η*(1 rad/s, 25 C)

Viscoelastic behavior at 25°C (in the melt state)

1 2 Two regimes τ ≈ f(φsticker )t for Mw ≤ 20kg/mol τ ≈ f(LPnBA) for Mw ≥ 20kg/mol

Probe-tack Experiments – Flat Punch

Adhesion of thin acrylic films

Contact (t ≈ 10s) Debonding (V= 100µm/s) Thin Film (h≈100µm) Steel probe (Ф ≈1cm) Viscoelastic / Viscous Elastic Adhesion Energy Wadh (J/m2) Introduction Copolymer & Resins Bis-Urea PnBA

Adhesion test

Introduction Copolymer & Resins Bis-Urea PnBA Probe-tack test (100µm/s) Steel Probe Wadh ≈ 30-50 J/m2

1.0 0.8 0.6 0.4 0.2 0.0 2.5 2.0 1.5 1.0 0.5 0.0 PnBAX5 PnBAX8 PnBAX115

ε σ (MPa) Wadh << Wadh (PSA) ≈ 100J/m2

Adhesion test

Introduction Copolymer & Resins Bis-Urea PnBA Probe-tack test (100µm/s) Steel Probe Wadh ≈ 30-50 J/m2

1.0 0.8 0.6 0.4 0.2 0.0 2.5 2.0 1.5 1.0 0.5 0.0 PnBAX5 PnBAX8 PnBAX115

ε σ (MPa) Wadh << Wadh (PSA) ≈ 100J/m2 Entangled Chains A high Density of Sticker

+

How to strengthen

• ur supramolecular system ?

Supramolecular Copolymers & Resins

Entangled Chains with several stickers per chain Incorporate reactive monomers in the side chains of our PnBAX Cross-link partially with cross-linker (or hardener) Introduction Copolymer & Resins Bis-Urea PnBA

Supramolecular Copolymers & Resins

Hardener Diamine

N H2 NH2

Introduction Copolymer & Resins Bis-Urea PnBA Polar Core Side Chain Side Chain Chemical Parameters for the copolymer structure Mw ≈ 10kg/mol 8 GMA per polymer chain Epoxy

10 10

1

10

2

10

3

10

4

G' & G'' (Pa) 0.01 0.1 1 10 100 Angular Velocity (rad/s)

Introduction Copolymer & Resins Bis-Urea PnBA

Copolymer without Xylene Core

Frequency Dependence for G’ & G’’ at 25°C

Uncross-linked Copolymer Lightly Cross-linked Copolymer w%(hardener) = 0,8%

G’ G’’

10 10

1

10

2

10

3

10

4

G' & G'' (Pa) 0.01 0.1 1 10 100 Angular Velocity (rad/s)

Introduction Copolymer & Resins Bis-Urea PnBA

Copolymer without Xylene Core

Frequency Dependence for G’ & G’’ at 25°C

Strengthening our PnBA Matrix by Chemical Cross-linking Uncross-linked Copolymer Lightly Cross-linked Copolymer w%(hardener) = 0,8%

600x10

3

400 200 Stress (Pa) 4 3 2 1 Strain

47 J/m2 Adhesive Failure 11J/m2 Cohesive Failure

G’ G’’

Introduction Copolymer & Resins Bis-Urea PnBA High Viscoelastic Moduli Strong Interactions between Epoxy / Xylene Strengthening our PnBA Matrix by Epoxy / Urea Interaction

Copolymer with Xylene Core

N H O N H R R O R

Probe-tack 100µm/s – Steel Probe 0,04% 104 J/m2 104 J/m2 Adhesive Debonding High Improvement of Adhesive Properties Cohesive Debonding Strain Stress (Pa) Introduction Copolymer & Resins Bis-Urea PnBA

Copolymer with sticker

35 J/m2 Cohesive Debonding

Conclusion

Center-functionalized PnBA Center-functionalized Pn(BA-GMA) lightly Cross-linked Viscoelastic Fluids Soft Dissipative Solid Supramolecular Interactions + Chemical Cross-linking Promising Adhesion