PMID- 20707539
OWN - NLM
STAT- MEDLINE
DCOM- 20101122
LR  - 20121115
IS  - 1089-7690 (Electronic)
IS  - 0021-9606 (Linking)
VI  - 133
IP  - 5
DP  - 2010 Aug 7
TI  - Mesoscale spatial distribution of electron spins studied by time-resolved 
      small-angle and ultrasmall-angle neutron scattering with dynamic nuclear 
      polarization: a case of 2,2,6,6-tetramethylpiperidine 1-oxyl (TEMPO) doped in 
      high-density polyethylene.
PG  - 054504
LID - 10.1063/1.3460923 [doi]
AB  - We carried out time-resolved small-angle neutron scattering (SANS) and 
      ultrasmall-angle neutron scattering (USANS) studies of dynamically polarized 
      high-density polyethylene (HDPE) doped with 2,2,6,6-tetramethylpiperidine 1-oxyl 
      (TEMPO) persistent free radicals. We observed a remarkable enhancement of the 
      scattering intensity shortly after a switching of microwave frequency from 
      positive (negative) to negative (positive) dynamic nuclear polarization (DNP). 
      The enhancement was found to be due to spatially heterogeneous proton-spin 
      polarization generated as a result of heterogeneously distributed TEMPO in the 
      HDPE sample. The spatial fluctuation of the polarization ranged up to the 
      length-scale of > or = 100 nm. This result strongly suggests that the TEMPO free 
      radicals are localized more in nonfibrils but less in fibrils of HDPE. In this 
      way, we propose that the time-resolved DNP-SANS and DNP-USANS be general 
      techniques to determine mesoscale spatial distribution of electron spins in 
      dielectric materials.
FAU - Kumada, Takayuki
AU  - Kumada T
AD  - Quantum Beam Science Directorate, Kansai Photon Science Institute, Japan Atomic 
      Energy Agency, Umemidai, Kizugawa, Kyoto 619-0215, Japan. 
      kumada.takayuki@jaea.go.jp
FAU - Noda, Yohei
AU  - Noda Y
FAU - Koizumi, Satoshi
AU  - Koizumi S
FAU - Hashimoto, Takeji
AU  - Hashimoto T
LA  - eng
PT  - Journal Article
PT  - Research Support, Non-U.S. Gov't
PL  - United States
TA  - J Chem Phys
JT  - The Journal of chemical physics
JID - 0375360
RN  - 0 (Cyclic N-Oxides)
RN  - 0 (Free Radicals)
RN  - 9002-88-4 (Polyethylene)
RN  - VQN7359ICQ (TEMPO)
SB  - IM
MH  - Cyclic N-Oxides/*chemistry
MH  - *Electrons
MH  - Free Radicals/chemistry
MH  - Polyethylene/*chemistry
MH  - Scattering, Small Angle
MH  - Time Factors
MH  - X-Ray Diffraction
EDAT- 2010/08/17 06:00
MHDA- 2010/12/14 06:00
CRDT- 2010/08/17 06:00
PHST- 2010/08/17 06:00 [entrez]
PHST- 2010/08/17 06:00 [pubmed]
PHST- 2010/12/14 06:00 [medline]
AID - 10.1063/1.3460923 [doi]
PST - ppublish
SO  - J Chem Phys. 2010 Aug 7;133(5):054504. doi: 10.1063/1.3460923.