Dear Ravi, if you  want to get an amorphous form of a semi-crystalline polymer without chemical modification, you could heat it past its melting point and then quench it (rapidly, say in liq N2). This will prevent recrystallization, but although easy to achieve in say a DSC pan, will be technically challenging on a larger scale.  Any future heating past its crystallization temperature will of course lead to recrystallization.  Best regards. Deon

Dear Ravi, if you  want to get an amorphous form of a semi-crystalline polymer without chemical modification, you could heat it past its melting point and then quench it (rapidly, say in liq N2). This will prevent recrystallization, but although easy to achieve in say a DSC pan, will be technically challenging on a larger scale.  Any future heating past its crystallization temperature will of course lead to recrystallization.  Best regards. Deon

As amorphous form is a metastable phase there is no true permanent form, but you can inhibit crystallization by addition of a crystallization inhibitor or trap the amourphous form in a matrix to inhibit crystallization.

Addition of reagents rapidly with high speed agitation and pH increase at strongly alkaline value (pH 13-14) gives amorphous precipitate. This observation is noted when I prepare polyvalent metal oxides.

If you try Deon's suggestion you must keep in mind that any quenched material will gain cristallinity slowly, actually such change is related to the storing temperature (the higher, the faster). Also remember that quenched materials becomes brittle, therefore handling may become a problem. Good Luck!!!

Some crystalline materials can be reduced to an amorphous form by grinding.  Gibbsite for example. There is a paper available here on ResearchGate that mentions this. 

Thermal decomposition of mechanically activated gibbsite

K. J. D. MacKenzie,J. Temuujin, K. Okada

Thermochimica Acta 327 (1999) 103±108

Ravi, you should give more details about what you are trying to do. Depending of the type of material, thickness... the best method will vary greatly.

Here is an example not given yet: ion implantation of Silicon, turn silicon wafers amorphous (at least the layer which has been implanted). Annealing will return the silicon to its crystalline state. 

In case of a water soluble material you might dissolve the crystals and apply lyophilisation including shock freezing. This delivers the highest amount of amorphous material.

Dear Thierry Dubroca  i am using crystalline drug Ciprofloxacin Hcl with polymers in melt extrusion

A reference on predictions of amorphous potential of several drugs are available on researchgate:

Early Drug Development Predictions of Glass-Forming Ability and Physical Stability of Drugs.

Denny Mahlin, Christel A S Bergström

Department of Pharmacy, Uppsala University, Uppsala, Sweden. Electronic address: .

European journal of pharmaceutical sciences: official journal of the European Federation for Pharmaceutical Sciences (Impact Factor: 2.61). 04/2013; DOI: 10.1016/j.ejps.2013.03.016

Source: PubMed

Fundamentally, there are two ways you can make a material amorphous:

1. Take a disordered, molten state, and rapidly freeze it, as Deon had already suggested. This is how every glass in the world is made. You main question with this approach becomes of how fast your material needs to be cooled. (e.g. silica -- no rush, metallic alloy -- up to 10^6K/second). Another factor to keep in mind is the crystallization temperature: it's generally above glass transition and below melting, but if for your material it is around room temp, then your amorphous material can gradually recrystallize unless refrigferated.

2. Take an originally crystalline material, and introduce enough dislocations into the crystal lattice, to where it is sufficiently disordered to be considered amorphous. As Peter suggested, this could be done by continuous deformation, such as grinding, often done in liquid nitrogen. Another way would be to irradiate your material, which is how most of the universe does it (stellar dust is heavily amorphous), but on this planet it's really a rare, specialty processing method.

Best of luck.

Dear Ravi

Sometimes confinement also leads to amorphous form. You may try that route.

With best reagrds

Dear Ravi,

Heat you sample up to its melting point and quench immediately let us say 50 degree per minute to -10 degree. You may get amorphous form. You can see the polymorph conversion in your second heating run or with PXRD of quenched sample.

Dear Ravi.

1. you try once by spray dryer also, dissolve the compound in suitable solvent even if it soluble in water also ok. then convert the amorphous by using spray drier. only thing is instrument is little expensive.

2. try to re-precipitate by using polar solvents like DMSO by using co-solvents. Good luck by Dr. Paramesh