142 Advances in Polymer Science Editorial Board: A. Abe. A.-C ...

204 J. Roovers, B. Comanita
Scheme 10
(M b~2000 D) are flattened on deposition and are unchanged on annealing, leaving
a largely intact film.
Fréchet and coworkers recently described how living free radical polymerization
can be used to make dendrigrafts. Either 2,2,6,6-tetramethylpiperidine oxide
(TEMPO) modified polymerization or atom transfer radical polymerization
(ATRP) can be used [96] (see Scheme 10). The method requires two alternating
steps. In each polymerization step a copolymer is formed that contains some
benzyl chloride functionality introduced by copolymerization with a small
amount of p-(4-chloromethylbenzyloxymethyl) styrene. This unit is transformed
into a TEMPO derivative. The TEMPO derivative initiates the polymerization
of the next generation monomer or comonomer mixture. Alternatively,
the chloromethyl groups on the polymer initiate an ATRP polymerization in the
presence of Cu I Cl or Cu I Cl-4,4' dipyridyl complex. This was shown to be the case
for styrene and n-butylmethacrylate. SEC shows clearly the increase in molecu-