Generally montmorillonite clay is used for clay-polymer composite preparation as it has 2:1 layered structure and expanding lattice. The microstructure of such composites can be different types like phase separated, intercalated or exfoliated. As you rightly said that exfoliation is a delaminating process, so in exfoliated microstructure the platelets move far apart from each other and their periodicity is completely lost. If the polymer chains arrange between two platelets in such a way that the electrostatic force between them is completely overcome, then exfoliated microstructure can be obtained. On the other hand, in case of intercalated microstructure the periodicity of clay platelets remain intact while the polymer chains enter into the clay interlayers. In reality during preparation of such composites both type of structures are obtained. Though it depends on type of polymers being used and techniques used for composite preparation, but getting a completely exfoliated or completely intercalated microstructure is difficult. Different extent of intercalation as well exfoliation can be observed together. Qualitative measurement can be done in this regard. Completely exfoliated microstructure should not generate any diffraction peak in X-ray diffractogram, whereas, intercalated microstructure should give a signal. However, it again depends on various factors like crystal defect, orientation etc. But intensity of the X-ray diffraction peak can give an idea about the type of microstructure. TEM can give a more realistic picture. But probably you will get a mixture of both the microstructures in whatever way you prepare your composite using whichever polymer you require. So for obvious reason, X-ray diffraction will give the average value of the expansion of the intercalated microstructure but not of the exfoliated.

I suggest you to follow the literature of Lonkar and Heinrich for clay exfoliation and related issues.

The mostly used method for clay exfoliation is organophilization with cationic compouds, such as quaternary ammonium salts with long alkyl chains. During that process a sodium (or calcium, it isdepend on clay type) atom is exchange for cation from ammonium salt and alkyl chains widen the spacebetween platellets. (but in most cases, it cause intercalation). There are also other methods to clay exfoliation e.g. disspersion  of clay in more hydrophilic matrices (mixing parameters are key issues) with e.g ultrasonic treatment. Organophilic clays are use mianly for more hydrophobic matrices. Clay exfoliation/disspersion degree are investigated with e.g. XRD and TEM. Quaternary salts can have semi-, hydrophilic or hydrophobic character, which is base for further application. (type of modifying salt shoul be compatibile to polymer matrix.

See also :

Polymer nanotechnology: Nanocomposites

D.R. Paul , L.M. Robeson

Polymer 49 (2008) 3187–3204

Mechanism of Clay Tactoid Exfoliation in Epoxy-Clay Nanocomposites

Tie Lan , Padmananda D. Kaviratna , Thomas J. Pinnavaia

Chem. Mater., 1995, 7 (11), pp 2144–2150

I guess it depends which minerals are you trying to. Some are very easy, such as montmorillonite. It even can be exfoliated only in Na+ solution, while some others may very hard such as kaolinite.

Generally montmorillonite clay is used for clay-polymer composite preparation as it has 2:1 layered structure and expanding lattice. The microstructure of such composites can be different types like phase separated, intercalated or exfoliated. As you rightly said that exfoliation is a delaminating process, so in exfoliated microstructure the platelets move far apart from each other and their periodicity is completely lost. If the polymer chains arrange between two platelets in such a way that the electrostatic force between them is completely overcome, then exfoliated microstructure can be obtained. On the other hand, in case of intercalated microstructure the periodicity of clay platelets remain intact while the polymer chains enter into the clay interlayers. In reality during preparation of such composites both type of structures are obtained. Though it depends on type of polymers being used and techniques used for composite preparation, but getting a completely exfoliated or completely intercalated microstructure is difficult. Different extent of intercalation as well exfoliation can be observed together. Qualitative measurement can be done in this regard. Completely exfoliated microstructure should not generate any diffraction peak in X-ray diffractogram, whereas, intercalated microstructure should give a signal. However, it again depends on various factors like crystal defect, orientation etc. But intensity of the X-ray diffraction peak can give an idea about the type of microstructure. TEM can give a more realistic picture. But probably you will get a mixture of both the microstructures in whatever way you prepare your composite using whichever polymer you require. So for obvious reason, X-ray diffraction will give the average value of the expansion of the intercalated microstructure but not of the exfoliated.

you can do this with small organic molecule as HCL, DSMO, and glycerin

I have a submission of an article for kaolin

Typical clays, prior to exfoliation, have a layered structure with a gap of about 0.1 nm between each layer and positively charged ions on the surface of each layer. The positively charged ions are attached by an ionic interaction with the negative surface of the clay layers, and create a net neutral charge between clay layers.

Traditional exfoliation is generally conducted as follows. Clay is first swelled by placing it in water. Swelling takes place because the positively charged ions become solubilized in the water, leaving adjacent negatively charged clay layers. The adjacent clay layers are repulsed by their similar negative charges, resulting in gaps of up to about 3 nm between the layers. An organic salt, such as cetyltrimethylammonium bromide or benzalkonium chloride is then added to the swollen clay to form an organo-clay. The organic salt is attracted to the negatively charged surface of the clay, keeping the swelling state stable and gaps of about 5-10 nm between the layers. This organo-clay is then dried and subsequently placed in an organic solvent, such as toluene. A polymer such as polypropylene or nylon is then added to further separate the layers of the clay. Moreover, the polymer is attracted to the organic salt and therefore penetrates between clay layers. The large molecule size of the polymer serves to counteract any remaining Van der Waals interactions between the layers and the clay becomes fully exfoliated, i.e. separated into discrete layers.

The easiest way to detect the exfoliation is by using X-ray diffractometry. The absence of the peak of the basal spacing confirms the exfoliation.

Thanks to all f u ..

I've some doubts related to this topic. I'm working on polymer modification of bentonite to enhance its barrier properties.

How anionic polymers cause exfoliation of clay platelets?

I found many explanations. One is polymers are attracted to positive edge of clay at low pH condition. But the positive charge of clay is very small when compared to negative charge. So net repulsive force will be more than that of attraction towards edge. Then how edge to edge contact with clay platelets promote exfoliation?

Another explanation is interlayer cations act as bridge between anionic polymer and negatively charged clay surface. Since cations are bounded with water, how this will be possible?

Another explanation provided is H+ ions replace the Na+ ions at low pH condition. But cation bridge phenomenon and this one cannot go hand in hand.

Does anionic polymer acts in the interlayer to overcome the electrostatic force between two layers?