Inkbottle pores

A pore communicating with or connected to the surface of a porous body. (See also inkbottle pore.)... 

A type H2 hysteresis loop has a triangular shape and a very steep desorption branch. Such behavior was observed for many porous inorganic oxides and was attributed to pore coimectivity effects [80], which were often defined as the presence of pores with narrow mouths (inkbottle pores), but the latter identification may be grossly oversimplified [50]. Indeed, triangular hysteresis loops were observed even for highly ordered MCM-41 materials with pore sizes of about 4-5 nm [39,55,57]. For such samples, desorption (capillary evaporation) of nitrogen from primary mesopores takes place at relative pressures of 0.4-0.5, i.e., in the region where... 

Mercury intrusion data also may be misleading for porous materials having many inkbottle type pores, cp. middle portion of Fig. 1.1. In such situations high pressures are needed to overcome resistance of mercury to pass the narrow neck of the pore, i. e. the wider portion of the inkbottle pores will not be adequately reflected in the experimentally taken Vhj = Vng (p) curve. However, despite these disadvantages, mercury intrusion experiments often gives valuable information concerning the macro- and mesopores of a sorbent and hence very well may be used for comparative measurements and quality tests of sorbent samples. 

The geometrical structure of pores is of great concern, but the three-dimensional description of pores is not established in less-crystalline porous solids. Only intrinsic crystalline intra-particle pores offer a good description of the structure. The hysteresis analysis of molecular adsorption isotherms and electron microscopic observation estimate the pore geometry such as cylinder (cylinder closed at one end or cylinder open at both ends), cone shape, slit shape, interstice between closed-packing spheres and inkbottle. However, these models concern with only the unit structures. The higher order structure of these unit pores such as the network structure should be taken into accoimt. The simplest classification of the higher order structures is one-, two- and three-dimensional pores. Some zeolites and aluminophosphates have one-dimensional pores and activated carbons have basically two-dimensional slit-shaped pores with complicated network structures [95]. 

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