PMID- 26893528
OWN - NLM
STAT- PubMed-not-MEDLINE
LR  - 20240327
IS  - 0024-9297 (Print)
IS  - 1520-5835 (Electronic)
IS  - 0024-9297 (Linking)
VI  - 49
IP  - 1
DP  - 2016 Jan 12
TI  - How Do Spherical Diblock Copolymer Nanoparticles Grow during RAFT Alcoholic 
      Dispersion Polymerization?
PG  - 172-181
AB  - A poly(2-(dimethylamino)ethyl methacrylate) (PDMA) chain transfer agent (CTA) is 
      used for the reversible addition-fragmentation chain transfer (RAFT) alcoholic 
      dispersion polymerization of benzyl methacrylate (BzMA) in ethanol at 70  degrees C. THF 
      GPC analysis indicated a well-controlled polymerization with molecular weight 
      increasing linearly with conversion. GPC traces also showed high blocking 
      efficiency with no homopolymer contamination apparent and M(w)/M(n) values below 
      1.35 in all cases. (1)H NMR studies confirmed greater than 98% BzMA conversion 
      for a target PBzMA degree of polymerization (DP) of up to 600. The PBzMA block 
      becomes insoluble as it grows, leading to the in situ formation of sterically 
      stabilized diblock copolymer nanoparticles via polymerization-induced 
      self-assembly (PISA). Fixing the mean DP of the PDMA stabilizer block at 94 units 
      and systematically varying the DP of the PBzMA block enabled a series of 
      spherical nanoparticles of tunable diameter to be obtained. These nanoparticles 
      were characterized by TEM, DLS, MALLS, and SAXS, with mean diameters ranging from 
      35 to 100 nm. The latter technique was particularly informative: data fits to a 
      spherical micelle model enabled calculation of the core diameter, surface area 
      occupied per copolymer chain, and the mean aggregation number (N(agg)). The 
      scaling exponent derived from a double-logarithmic plot of core diameter vs PBzMA 
      DP suggests that the conformation of the PBzMA chains is intermediate between the 
      collapsed and fully extended state. This is in good agreement with (1)H NMR 
      studies, which suggest that only 5-13% of the BzMA residues of the core-forming 
      chains are solvated. The N(agg) values calculated from SAXS and MALLS are in good 
      agreement and scale approximately linearly with PBzMA DP. This suggests that 
      spherical micelles grow in size not only as a result of the increase in copolymer 
      molecular weight during the PISA synthesis but also by exchange of individual 
      copolymer chains between micelles and/or by sphere-sphere fusion events.
FAU - Jones, E R
AU  - Jones ER
AD  - Dainton Building, Department of Chemistry, University of Sheffield , Brook Hill, 
      Sheffield, South Yorkshire S3 7HF, U.K.
FAU - Mykhaylyk, O O
AU  - Mykhaylyk OO
AD  - Dainton Building, Department of Chemistry, University of Sheffield , Brook Hill, 
      Sheffield, South Yorkshire S3 7HF, U.K.
FAU - Semsarilar, M
AU  - Semsarilar M
AD  - DSM Ahead , P.O. Box 18, 6160 MD Geleen, The Netherlands.
FAU - Boerakker, M
AU  - Boerakker M
AD  - DSM Ahead , P.O. Box 18, 6160 MD Geleen, The Netherlands.
FAU - Wyman, P
AU  - Wyman P
AD  - DSM Ahead , P.O. Box 18, 6160 MD Geleen, The Netherlands.
FAU - Armes, S P
AU  - Armes SP
AD  - Dainton Building, Department of Chemistry, University of Sheffield , Brook Hill, 
      Sheffield, South Yorkshire S3 7HF, U.K.
LA  - eng
GR  - 320372/ERC_/European Research Council/International
PT  - Journal Article
DEP - 20151228
PL  - United States
TA  - Macromolecules
JT  - Macromolecules
JID - 0365316
PMC - PMC4745608
COIS- The authors declare no competing financial interest.
EDAT- 2016/02/20 06:00
MHDA- 2016/02/20 06:01
PMCR- 2016/02/08
CRDT- 2016/02/20 06:00
PHST- 2015/11/02 00:00 [received]
PHST- 2015/12/03 00:00 [revised]
PHST- 2016/02/20 06:00 [entrez]
PHST- 2016/02/20 06:00 [pubmed]
PHST- 2016/02/20 06:01 [medline]
PHST- 2016/02/08 00:00 [pmc-release]
AID - 10.1021/acs.macromol.5b02385 [doi]
PST - ppublish
SO  - Macromolecules. 2016 Jan 12;49(1):172-181. doi: 10.1021/acs.macromol.5b02385. 
      Epub 2015 Dec 28.