Though it is hard to have hydrogen bonding with Si O2, but it is not tough, use one adapt or molecule and bind it with terminal group of agar side chain, or hydrolyze the  agar partially and add silica in presence of an strong alkali or a reagent with more free radicals or having a metal group of a inert group with some energy.

Pls  read third paragraph under Experimental, Results and Discussion on page 1403

Of the paper:

J. Geotech.Geoenviron. Eng. 2013.139:1402-1406.

Because both the agar and sand are slightly negative in charge, addition of a few drops of positively charged starch[starpol 136 and starpol 469] would cause adhesion.

Thank you both for your response. The paper you mentioned is the one I am referring. But I wanted to know if the hydrogen bond can exist even without addition of starch.Actually sand is neutral and it is said to have no surface charge.The negative charge mentioned in the paper may be due to little bit of clay present in natural sandy soils, which I am assuming.

In the same paper under the heading bio polymer selection they have mentioned about an alternate possibility of hydrogen bond formation which had lead me to my query.And also agar has hydroxyl group.

Yes, although in general it is unlikely that agar gel (mostly water by weight) will get close enough to the surface of the silica for this to be important. Surface tension interactions with the water phase of your gel is probably the biggest contributor for agar gel sticking to a sand particle.

Dear Smitha Sivadasan

In Direct way the Hydrogen bond between Agar and Sand does not possible, but some binding may possible, it does not mean hydrogen bonding,

Sand almost neutral charge and agar have slightly +ve charge but in the case of sand that does not have any functional H+ or H- ion so some attraction between sand and agar possible but bonding not possible in this condition.,

If you want to do means you take processed sand from this you can able to create some -ve charge without change in nature of sand and then you try for this hydrogen bonding it's easily sossible.,

And also vary hard to have hydrogen bond with SiO2 but now recently some functional reaction between Agar was found so by using this you can able to do this., if you succeed in this, you may be get more impact via international patient.,

Good Luck & Regards

R.Selva.....

Dear Selva,

Thank you for your answer. But I had a query about one of the things you wrote.You had mentioned agar has slight +ve charge, which is contrary to what I read in some papers which says agar is slightly negatively charged.Can you please clarify?