Low surface energy pu film with small contact angle hysteresis
Download
1 / 25

Low Surface Energy PU Film With Small Contact Angle Hysteresis - PowerPoint PPT Presentation


  • 84 Views
  • Uploaded on

Low Surface Energy PU Film With Small Contact Angle Hysteresis. Dou Qizheng 05-09-19. Beautiful lotus flowers. Water droplets. Self-cleaning. Surface roughness. Bar = 20 m. Introduction. lotus-effect. Barthlott, et al. Planta 1997 , 202 , 1.

loader
I am the owner, or an agent authorized to act on behalf of the owner, of the copyrighted work described.
capcha
Download Presentation

PowerPoint Slideshow about ' Low Surface Energy PU Film With Small Contact Angle Hysteresis' - forrest-riddle


An Image/Link below is provided (as is) to download presentation

Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author.While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server.


- - - - - - - - - - - - - - - - - - - - - - - - - - E N D - - - - - - - - - - - - - - - - - - - - - - - - - -
Presentation Transcript

Introduction

Beautiful lotus flowers Hysteresis

Water droplets

Self-cleaning

Surface roughness

Bar = 20 m

Introduction

lotus-effect

Barthlott, et al. Planta1997, 202, 1


Wenzel eq.

Cassie-Baxter eq.

: contact angle on a rough surface

0: contact angle on a projected ‘smooth’ surface

Surface roughnessenhances the hydrophobicity of hydrophobic surfaces

Self-Cleaning Properties

  • Hydrophobic surface with low surface energy

  • water contact angle,  > 90°

  • Low roll-off angles ------ small contact angle hysteresis


Basic theory Hysteresis

  • The force needed for a drop to move over a solid surface (F ):

    F ~ LV (cos R– cos A)

    LV is the surface tension of the liquid

  • Contact angle hysteresis:

    A–R or LV (cos R– cos A)


Fluorinated Polyurethane Films Hysteresis

  • Water contact angle:

  • Advancing: 120º, receding: 60-70º

  • Huge hysteresis: primarily due to the surface reorganization during the contact angle measurements.

LEIS (low-energy ion scattering)

First atomic layer, only F and C can be detected

  • PDMS

  • Hydrophobic

  • High MW to limit surface reorganization


Experimental
Experimental Hysteresis

  • Preparation of low-surface energy films

  • Polyurethane as polymer matrix

  • Poly (dimethyl siloxane) (PDMS) will be used as a low-surface energy agent


Polymer matrix s olventless l iquid o ligoesters slo and n3600 cross linker
Polymer Matrix: HysteresisSolventless Liquid Oligoesters (SLO) and N3600 (cross-linker)


Polyurethane films modified with hydroxyl terminated pdms
Polyurethane films modified with hydroxyl-terminated PDMS Hysteresis

Approach 1

PDMS + SLO + N3600 → PU film of low 

Approach 2

PDMS + N3600 → partially PDMS-modified N3600

SLO + N3600 + PDMS-N3600 → low  PU

(To increase the miscibility between PDMS and other components)


Bi functional pdms
Bi-functional PDMS Hysteresis

(1) EFKA 3299

HO-(EO)n-OCH2CH2CH2-(Si(Me)2O)x-CH2CH2CH2O-(EO)n-OH

n ca. 10

x ca. 20

EO = ethylene oxide, PO = propylene oxide

(2) 481246

HO-CH2CH2-OCH2CH2-(Si(Me)2O)n-CH2CH2O-CH2CH2-OH

n=69


Mono functional pdms
Mono-functional PDMS Hysteresis

Mono-hydroxyl terminated PDMS (480355):

n= 63


Surface wettability Hysteresis

PU film with bi-functional EFKA3299

Water CA and hysteresis of PU film containing EFKA 3299 and cured at room temperature by approach 1


Surface wettability Hysteresis

PU film with bi-functional 481246

PU film containing 481246 by approach 1


Surface wettability Hysteresis

PU film with bi-functional 481246

PU film containing 481246 by approach 1


Surface wettability Hysteresis

PU film with mono-functional 480355

PU film containing 480355 by approach 2


Surface wettability Hysteresis

PU film with mono-functional 480355

PU film containing 480355 by approach 2


Surface chemical composition Hysteresis

PU film with bi-functional 481246

PU film containing 481246 and cured at 80 oC


Surface chemical composition Hysteresis

PU film with mono-functional 480355

The chemical composition (Si%) of the PU films which were modified by different amount of 480355 and cured under different temperature.


Surface chemical composition Hysteresis

PU film with mono-functional 480355

The chemical composition (N%) of the PU films which were modified by different amount of 480355 and cured under different temperature.


Surface chemical composition Hysteresis

PU film with mono-functional 480355

The chemical composition (N% and Si%) in different depth of the PU films which were modified by0.07%wt (PDMS)63-OH and cured under 40 oC and 120 oC


Surface chemical composition Hysteresis

Compare the PU film with 480355 and 481246

The chemical composition (N% and Si%) in different depth of the PU films which were modified by0.07%wt (PDMS)63-OH or 0.08%wt (PDMS)69-(OH)2 and cured under 80 oC


Model Hysteresis

PU film containing EFKA 3299

PU film containing 480355

PU film containing 481246


Future plans
Future plans Hysteresis

  • 1. Increase the roughness of the surface by adding some nano-particles into the film as a additive to get a super-hydrophobic surface.


Future plans1
Future plans Hysteresis

  • 2. Application of PDMS-modified PU films as anti-fouling coatings.

  • Coatings containing toxic materials

  • Non-toxic Systems

    • Fouling-release coatings based on silicones

      • Perform well initially

      • Soft, poor durability, short use life


Acknowledgement
Acknowledgement Hysteresis

  • Dr. W. Ming

  • Prof. Wang

  • Prof. Lemstra

  • Dr. Karssenberg

  • EPG/SMG/SKT group members

  • DPI


THANK YOU FOR Hysteresis

YOUR ATTENTION


ad