Sol-Gel Gateway Home page

 

 

 

 
  Active TopicsActive Topics  Display List of Forum MembersMemberlist  Search The ForumSearch  HelpHelp
  RegisterRegister  LoginLogin
Chemistry
 Sol-Gel Gateway Forum>Sol-Gel Forum>Chemistry
Message Icon Topic: TiO2 Post Reply Post New Topic
Author Message
Venus
Newbie
Newbie


Joined: 12 April 2006
Online Status: Offline
Posts: 12
Quote Venus Replybullet Topic: TiO2
    Posted: 22 July 2006 at 5:08am

Hello!

My question is this: in the sol-gel method, how does hydrolysis happen? with the water present in the air, or do we have to actually add water to the precursor?

And about aging,  how long should we wait for the mixture to age, 24 hours or more...?

Thanks
IP IP Logged
Francisco
Newbie
Newbie
Avatar

Joined: 05 February 2005
Location: Colombia
Online Status: Offline
Posts: 5
Quote Francisco Replybullet Posted: 22 July 2006 at 1:23pm

Hi,

1.  The great majority of the precursors of TiO2 are air sensitive compounds, hence because the air contains water the hidrolisis begin only with the contact of the precursor and the air, but the air water“s quantity is very small for complete the hidrolysis satisfactory.  Then the best is add water to the precursor.

2.  This depends of the type of the sol gel method that you use (inorganic or organic), also of the type of structure that you desire to obtain (gel, sol, etc).

Bye.
Francisco J. Segura B.
Chemical Engineering B.Sc. student
Math B.Sc. student
Universidad de Los Andes
Bogotį, Colombia.
IP IP Logged
sagebob
Senior Member
Senior Member


Joined: 06 May 2005
Location: United States
Online Status: Offline
Posts: 193
Quote sagebob Replybullet Posted: 14 October 2006 at 2:52pm

howdy,

I would add that the type of solution determines where the hydrolysis takes place. 

With an anhydrous solution, all the water must come from the humidity int he air.  As Francisco mentions, the rate of reaction is relatively slow since the concentration is low.  This can however, lead to a perfectly adequate film with excellent optical and mechanincal properties.  The slow reaction rate provides ample time for the film structure to form.  I have found this to be best for titanium based films.

A completely hydrolyzed solution does not need any atmospheric moisture.  sometimes drying is a problem. I have found this to be best for silicon based solutions.

-bob
IP IP Logged
Post Reply Post New Topic
Printable version Printable version

Forum Jump 		You cannot post new topics in this forum
You cannot reply to topics in this forum
You cannot delete your posts in this forum
You cannot edit your posts in this forum
You cannot create polls in this forum
You cannot vote in polls in this forum




This page was generated in 0.055 seconds.
Privacy statement Copyright 2000-2013, Solgel.com.