Cauliflower polymer

De Gennes and Hervet 46 statistically found that these cauliflower polymers 8 (Tomalia s PAMAMs) exhibit restricted idealized growth, also known as dense packing , when the number of generations m = mi, where mi = 2.88 (In P + 1.5). This relates in space to the limiting radius Ru which increases linearly with P monomers. Below this limit, the radius R(M) of the dendrimer, when plotted as a function of molecular weight (M), should increase (m0,2) whereas above this limit (R > Ri), compact structures (R == A/0,33) should result. 

Wallace H. Carothers. Polymers and Polyfunctionality. Transactions of the Faraday Society. 32 (1936) 39-53. Carothers Cambridge speech is the source for polymers providing the bulk of living things Collins cauliflower mass and no mention of nylon. 

Dendrimers, or arborols, or cascade, or cauliflower, or starburst polymers, were first synthesized in the early 1980s [3,4]. In 1985 Tomalia et al. [5] and Newkome et al. [6] presented the first papers dealing with dendrimers. A multitude of dendrimers have been presented in the literature ranging from polyami-doamine [7,8],poly(propylene imine) [9,10], aromatic polyethers [11-13] and polyesters [14, 15], aUphatic polyethers [16] and polyesters [17], polyalkane [18-19], polyphenylene [20], polysilane [21] to phosphorus [22] dendrimers. Combinations of different monomers as well as architectural modifications have also been presented. For example, chirality has been incorporated in dendrimers [23,24]. Copolymers of linear blocks with dendrimer segments (dendrons) [25-27] and block-copolymers of different dendrons have been described [28]. 

Hr he first observations of popcorn (PC) polymer formation go back to the beginning of this century when Kondakow (J) studied the polymerization of dimethylbutadiene. The name popcorn polymers, however, is of much more recent origin. It was first used in the U.S. in 1940, where the similarity of appearance of these materials to a sponge or to cauliflower was replaced by the obviously more popular popcorn. Today, it is possible to prepare polymers of this type having no similarity at all to popcorn, but the name is retained. 

It has been shown8 that a cauliflower structure was observed for polymers grown from water because of hydrophobic effects. Such unevenness decreases conductivity. Aavapiriyanont and coworkers9 have also shown that the presence of small amounts of water affects the rate of growth and polymer conductivity. More recently, Trivedi and coworkers have shown that conducting polymers grown from ionic liquids have improved conductivity.10... 

Brownian motion and geography. Universe and cauliflowers — it is really astonishing how far mathematics can generalize... However, let s get back to polymers. How can all this stuff possibly be related to them ... 

Kinetics, degrees of polymerization, and constitution can be changed, however, by a series of other reactions (see Section 20.4). Under certain conditions, for example, the appearance of cauliflower-shaped forms, frequently representing cross-linked polymers, is observed (popcorn polymerization). 

The chemical structure of the counterion may have a profound influence on the morphology and conductivity of the polymer. For instance, polypyrrole made in the presence of dodecyl sulfate is very smooth, dense, stable, and highly conducting, whereas polypyrrole made in the presence of perchlorate ion has a cauliflower morphology and its conductivity is about 100 times lower than with dodecyl sulfate. Apparently long-chain anions have a kind of aligning effect on the polymer chains. Also, anions and other... 

Polyaniline (PANI) represents one of the most cited examples of nanostructured polymers, due to its outstanding electronic properties and technological applications that have promoted a wide number of studies and publications. Although a variety of different and peculiar morphologies have been reported, such as brain like [92], cauliflowers [93], nanoflakes, nanospheres and nanorods [94], chrysan-fhemum flower-like [95], plate-like structures and flower-like superstructures [96],... 

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