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Chem, Volume 2 Supplemental Information Ultra-High Molecular Weights via Aqueous Reversible-Deactivation Radical Polymerization R. Nicholas Carmean, Troy E. Becker, Michael B. Sims, and Brent S. Sumerlin
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Chem, Volume 2

Supplemental Information

Ultra-High Molecular Weights via Aqueous

Reversible-Deactivation Radical Polymerization

R. Nicholas Carmean, Troy E. Becker, Michael B. Sims, and Brent S. Sumerlin

Table  of  Contents  

2)   Materials  and  characterization  

3-­‐4)   Experimental  procedure  

5)   Figure  S1.  UHMW  polymerization  targeting  1.06  ´  106  g/mol  with  trithiocarbonate  iniferter.  

6)   Figure  S2.  UHMW  polymerization  targeting  2.04  ´  106  g/mol  with  trithiocarbonate  iniferter  

7)   Figure  S3.  UHMW  polymerization  targeting  5.11  ´  106  g/mol  with  trithiocarbonate  iniferter  

8)   Figure  S4.  On/off  UHMW  polymerization  of  DMA  with  a  trithiocarbonate  iniferter  

9)   Figure  S5.  Trithiocarbonate  and  xanthate  iniferter  Beer-­‐Lambart  plot  

10)   Figure  S6.  UHMW  polymerization  targeting  1.34  ´  106  g/mol  with  xanthate  iniferter  

11)   Figure  S7.  UHMW  polymerization  targeting  2.32  ´  106  g/mol  with  xanthate  iniferter  

12)   Figure  S8.  UHMW  polymerization  targeting  5.17  ´  106  g/mol  with  xanthate  iniferter  

13)   Figure  S9.  UHMW  polymerization  targeting  9.93  ´  106  g/mol  with  xanthate  iniferter  

14)   Figure  S10.  UHMW  polymerization  mediated  by  sunlight  with  trithiocarbonate  iniferter  

15)     Figure  S11.  Temperature  profile  of  UHMW  polymerization  of  DMA  with  xanthate  and  trithiocarbonate  iniferter  

16)   Figure  S12.  Background  initiation  of  DMA  under  UV  irradiation  

17)   Figure  S13.  Polymerization  rates  of  UHMW  xanthate  mediated  polymerizations  

 

Materials    

All   chemicals   were   used   as   received,   unless   otherwise   noted.   2-­‐(2-­‐Carboxyethylsulfanylthiocarbonylsulfanyl)-­‐2-­‐methylpropionic   acid   and   ethyl   2-­‐((ethoxycarbonothioyl)thio)propanoate   were   synthesized   according   to   previous   reports.[1,2]  N,N-­‐Dimethylacrylamide   (DMA,   Sigma-­‐Aldrich,   99%)   was   passed   through   a   column   of   basic  alumina   to   remove   inhibitors   and   acidic   impurities   prior   to   polymerization.   N,N-­‐Dimethylformamide   (DMF,   >99%)   was   purchased   from   Sigma-­‐Aldrich.   Dimethyl   sulfoxide  (DMSO)  was  purchased  from  Fischer.  Water  (deionized  ASTM  type  II)  was  purchased  from  Aqua  Solutions,  Inc.    Nuclear   Magnetic   Resonance   (NMR)   Spectroscopy.   1H   NMR   spectra   were   recorded   in  deuterated   chloroform   (CDCl3,   Cambrdige   Isotopes),   deuterated  dimethyl   sulfoxide   (DMSO-­‐d6,  Cambrdige  Isotopes),  or  duterium  oxide  (D2O,  Cambrdige  Isotopes)  using  a  Varian  Mercury  300  or  Varian  Inova  500  MHz  spectrometer.    Size  Exclusion  Chromatography  (SEC).  Molecular  weights  and  molecular  weight  distributions  were  determined  via  multi-­‐angle  laser  light  scattering  size  exclusion  chromatography  (MALS-­‐SEC)  in  N,N-­‐dimethylacetamide  (DMAc)  with  50  mM  LiCl  at  50  °C  and  a  flow  rate  of  1.0  mL/min  (Agilent  isocratic  pump,  degasser,  and  autosampler;  ViscoGel  I-­‐series  10  μm  guard  column  and  two  ViscoGel  I-­‐series  G3078  mixed  bed  columns,  with  molecular  weight  ranges  0−20×103  and  0−10×106  g/mol,  respectively).  Detection  consisted  of  a  Wyatt  Optilab  T-­‐rEX  refractive  index  detector  operating  at  658  nm  and  a  Wyatt  miniDAWN  Treos  light  scattering  detector  operating  at  659  nm.  Absolute  molecular  weights  and  polydispersities  were  calculated  using  Wyatt  ASTRA  software.  The  absolute  molecular  weight  for  PDMA  was  determined  using  100%  mass  recovery,  a  multiangle  light  scattering  detector  and  the  Wyatt  ASTRA  software.  Each  polymer  was  dehydrated  by  lyophilization  and  dissolved  in  SEC  solvent  (£1  mg/mL)  at  least  24  h  prior  to  molecular  weight  characterization.    UV-­‐Vis  Spectroscopy.  All  measurements  were  performed  on  a  Molecular  Devices  SpectraMax  M2  Multimode  Microplate  Reader  at  25  °C.  Absorbance  measurements  were  conducted  with  150  μL  of  sample  on  clear  96-­‐well  microplates  (Greiner).  Calibration  curves  and  path  length  correction  were  constructed  using  the  integrated  SoftMax  Pro  software.    

Light  Intensity  was  measured  with  General  UV513AB  Digital  UV  AB  Light  Meter  calibrated  at  365  nm.  

 

Experimental  Typical  ultrahigh  molecular  weight  (UHMW)  polymerization  procedure  (DMA  polymerization  initiated  by  a   trithiocarbonate   targeting  Mn  ³   5.00  ´   106  g/mol).  DMA  (394  mg,  3.97  mmol)  and   trithiocarbonate   iniferter   (20.0   µg,   7.45   ´   10-­‐5   mmol   from   1.00   mg/mL   DMSO   stock  solution)  were   dissolved   in  water   (1.70  mL,   2  M   [DMA])   in   a   10  mL   Schlenk   flask,   and   DMF  (0.100  mL)  was  added  as  an  internal  standard.  The  iniferter  stock  solution  was  stored  between  2  and  6  °C  for  further  use.  Argon  was  bubbled  through  the  polymerization  solution  for  20  min.  The   reaction   vessel  was   positioned   2.50   cm   from   the  UV   light   source   for   an   intensity   of   7.0  mW/cm2,   and   polymerization   was   initiated   upon   irradiation.   Monomer   conversion   was  determined  by  1H  NMR  spectroscopy,  monitoring  the  disappearance  of  the  DMA  vinyl  peaks  (d,  1H,   5.60   ppm)   relative   to   DMF   (s,   1H,   8.02   ppm).   Each   reaction   aliquot   was   dried   by  lyophilization  and  dissolved  in  SEC  solvent  (£1  mg/mL)  at   least  24  h  prior  to  molecular  weight  characterization.    UHMW  PDMA-­‐b-­‐PDMA.  DMA   (417  mg,  4.20  mmol)   and   trithiocarbonate   iniferter   (0.100  mg,  3.72  ´  10-­‐4  mmol  from  1.00  mg/mL  DMSO  stock  solution)  were  dissolved  in  water  (3.70  mL  1  M  [DMA])  in  a  10  mL  Schlenk  flask  and  DMF  (0.100  mL)  was  added  as  an  internal  standard.  Argon  was   bubbled   through   the   polymerization   solution   for   20   min.   The   reaction   vessel   was  positioned  2.50  cm  from  the  UV  light  source  for  an  intensity  of  7.0  mW/cm2  and  polymerization  was   initiated  upon   irradiation.   The   reaction  was   irradiated   for   24  h   and   a   small   amount  was  removed   to   determine   monomer   conversion   via   1H   NMR   spectroscopy   by   monitoring   the  disappearance  of  the  vinyl,  DMA  peaks  (d,  1H,  5.60  ppm)  relative  to  DMF  (s,  1H,  8.02  ppm)  and  to  characterize  molecular  weight  via  SEC.  The  polymerization  of  the  PDMA  first  block  reached  >95%  monomer  conversion.  DMA  (420  mg,  4.24  mmol)  was  dissolved  in  water  (3.10  mL),  DMF  (0.100  mL),  and  the  preceding  PDMA  polymerization  mixture.  Argon  was  bubbled  through  the  viscous  solution  for  20  min,  and  chain  extension  was  initiated  upon  irradiation.    End-­‐group   photolytic   trapping  with   TEMPO   (PDMA-­‐Xanthate).   Low  molecular  weight   PDMA  was  prepared  with  a  xanthate  iniferter  similar  to  the  procedures  described  above.  PDMA-­‐XAN  (85.0  mg,  Mn,SEC  4500  g/mol,  1.89  ´  10-­‐2  mmol)  and  TEMPO  (59.0  mg,  3.77  ´  10-­‐1  mmol)  were  dissolved  in  DMSO  (0.800  mL)  and  DMF  (0.100  mL).  Argon  was  bubbled  through  the  solution  for  20  min.  The  reaction  vessel  was  positioned  2.50  cm  from  the  UV  light  source  to  give  an  intensity  of   7.0  mW/cm2,   and   photolysis   was   induced   upon   irradiation.   Photolytic   decomposition  was  determined  via  1H  NMR  spectroscopy  by  monitoring  the  disappearance  of  the  terminal  PDMA  methyne  proton  (b,  1H,  5.58  ppm)  adjacent  to  the  xanthate  iniferter  relative  to  the  methylene  protons  (b,  2H,  3.97  ppm)  of  the  xanthate  iniferter.    End-­‐group  photolytic   trapping  with  TEMPO   (PDMA-­‐Trithiocarbonate).  Low  molecular  weight  PDMA   was   prepared   with   a   trithiocarbonate   iniferter   similar   to   UHMW   procedure   defined  above.  PDMA-­‐TTC  (168  mg,  Mn,SEC  3500  g/mol,  4.80  ´  10-­‐2  mmol)  and  TEMPO  (150  mg,  9.60  ´  10-­‐1   mmol)   were   dissolved   in   DMSO   (0.800   mL)   and   DMF   (0.100   mL).   Argon   was   bubbled  through  the  solution  for  20  min.  The  reaction  vessel  was  positioned  2.50  cm  from  the  UV  light  source   to   give   an   intensity   of   7.0   mW/cm2,   and   photolysis   was   induced   upon   irradiation.  

 

Photolytic   decomposition   was   determined   via   1H   NMR   spectroscopy   by   monitoring   the  disappearance   of   the   terminal   PDMA   methyne   proton   (b,   1H,   5.58   ppm)   adjacent   to   the  trithiocarbonate  iniferter  relative  to  DMF  (s,  1H,  8.02  ppm).    Sunlight  mediated  polymerization  of  DMA  with  trithiocarbonate  iniferter.  DMA  (779  mg,  7.86  mmol)  and  trithiocarbonate  iniferter  (100  µg,  3.73  ´  10-­‐4  mmol  from  1.00  mg/mL  DMSO  stock  solution)  were   dissolved   in  water   (3.00  mL,   2  M   [DMA])   in   a   10  mL   Schlenk   flask,   and   DMF  (0.100  mL)  was  added  as  an  internal  standard.  Argon  was  bubbled  through  the  polymerization  solution  for  20  min.  Three  syringes  were  purged  with  argon  in  the  side  arm  of  the  Schlenk  flask,  and   the   reaction   vessel  was   covered   in   foil   then   transferred   to   the   roof   of   Sisler  Hall   on   the  campus   of   the  University   of   Florida   in  Gainesville,   FL.   The   polymerization  was   initiated   upon  removal   of   the   foil   mask.   To   keep   the   polymerization   under   constant   sunlight   irradiation,   a  balloon  was  filled  with  argon  and  transferred  to  the  roof  to  purge  the  side  arm  of  the  Schelnk  flask  during   removal  of   reaction  aliquots.  The  polymerization  was  quenched  by   removing   the  vessel   from   sunlight.   Monomer   conversion   was   determined   by   1H   NMR   spectroscopy,  monitoring  the  disappearance  of  the  DMA  vinyl  peaks  (d,  1H,  5.60  ppm)  relative  to  DMF  (s,  1H,  8.02  ppm).  Each   reaction  aliquot  was  dried  by   lyophilization  and  dissolved   in  SEC  solvent   (£1  mg/mL)  at  least  24  h  prior  to  molecular  weight  characterization.    Measurement  of  polymerization  exotherm.    DMA  (500  mg)  was  dissolved  in  water  (2.00  mL,  2  M   [DMA])   and   transferred   to   a   10   mL   Schlenk   flask   with   an   electronic   thermocouple   fitted  through  a   rubber   septa   in  place  of   a   glass   stopper.  Argon  was  bubbled   through   the  aqueous  solution  for  15  min.  With  a  slow  flow  of  argon  through  the  top  rubber  septa,   the  experiment  was   initiated  by   turning  on   the   light   source.   The   solution   temperature  was   recorded  every  5  min.   This   aqueous   solution   served   as   a   control   to   compare   against   and   active   DMA  polymerization  targeting  UHMW.     DMA  (500  mg,  5.04  mmol)  and  xanthate  iniferter  (70.0  µg,  3.15  ´  10-­‐4  mmol  from  1.00  mg/mL  DMSO  stock  solution)  were  dissolved  in  water  (2.00  mL,  2  M  [DMA])  and  transferred  to  a  10  mL  Schlenk  flask  with  an  electronic  thermocouple  fitted  through  a  rubber  septa  in  place  of  a  glass  stopper.  Argon  was  bubbled  through  the  aqueous  solution  for  15  min.  With  a  slow  flow  of  argon  through  the  top  rubber  septa,  the  polymerization  was  initiated  by  turning  on  the  light  source.  The  solution  temperature  was  recorded  every  5  min.     DMA   (500  mg,   5.04  mmol)   and   trithiocarbonate   iniferter   (85.0  µg,   3.16  ´   10-­‐4   mmol  from   1.00  mg/mL   DMSO   stock   solution)   were   dissolved   in  water   (2.00  mL,   2  M   [DMA])   and  transferred  to  a  10  mL  Schlenk  flask  with  an  electronic  thermocouple   fitted  through  a  rubber  septa  in  place  of  a  glass  stopper.  Argon  was  bubbled  through  the  aqueous  solution  for  15  min.  With  a   slow   flow  of  argon   through   the   top   rubber   septa,   the  polymerization  was   initiated  by  turning  on  the  light  source.  The  solution  temperature  was  recorded  every  5  min.      

 

 Figure   S1.   N,N-­‐Dimethylacrylamide   (DMA)   was   irradiated   with   long-­‐wave   UV   light   in   the  presence   of   a   trithiocarbonate   iniferter   to   produce   ultrahigh   molecular   weight   (UHMW)  poly(DMA).  The  polymerization  of  DMA  to  UHMW  (Mn,SEC  1.03  ´  106  g/mol)  displays  near-­‐linear  pseudo-­‐first   order   kinetics,   indicating   a   constant   radical   concentration   up   to   >95%  monomer  conversion.   Size-­‐exclusion   chromatography   (SEC)   traces   shift   to   shorter   elution   times   and  higher   molecular   weights   throughout   the   polymerization   was   the   SEC   traces   remain  monomodal.  The  predicted  molecular  weights  (Mn,  theory)  closely  matches  measured  values  (Mn,  

SEC)  as  monomer  conversion  increases,  while  molecular  weight  distributions  (Ð)  remained  low.  

 

 

 Figure   S2.   N,N-­‐Dimethylacrylamide   (DMA)   was   irradiated   with   long-­‐wave   UV   light   in   the  presence   of   a   trithiocarbonate   iniferter   to   produce   ultrahigh   molecular   weight   (UHMW)  poly(DMA).  The  polymerization  of  DMA  to  UHMW  (Mn,SEC  2.52  ´  106  g/mol)  displays  near-­‐linear  pseudo-­‐first   order   kinetics,   indicating   a   constant   radical   concentration   up   to   >95%  monomer  conversion.   Size-­‐exclusion   chromatography   (SEC)   traces   shift   to   shorter   elution   times   and  higher   molecular   weights   throughout   the   polymerization   was   the   SEC   traces   remain  monomodal.  The  predicted  molecular  weights  (Mn,  theory)  closely  matches  measured  values  (Mn,  

SEC)  as  monomer  conversion  increases,  while  molecular  weight  distributions  (Ð)  remained  low.  

 

 Figure   S3.   N,N-­‐Dimethylacrylamide   (DMA)   was   irradiated   with   long-­‐wave   UV   light   in   the  presence   of   a   trithiocarbonate   iniferter   to   produce   ultrahigh   molecular   weight   (UHMW)  poly(DMA).  The  polymerization  of  DMA  to  UHMW  (Mn,SEC  4.79  ´  106  g/mol)  displays  near-­‐linear  pseudo-­‐first   order   kinetics,   indicating   a   constant   radical   concentration   up   to   94%  monomer  conversion.   Size-­‐exclusion   chromatography   (SEC)   traces   shift   to   shorter   elution   times   and  higher   molecular   weights   throughout   the   polymerization   was   the   SEC   traces   remain  monomodal.   The   predicted  molecular  weights   (Mn,  theory)   closely  match  measured   values   (Mn,  

SEC)  as  monomer  conversion  increases,  while  molecular  weight  distributions  (Ð)  remained  low.  

 

 Figure   S4.   N,N-­‐Dimethylacrylamide   (DMA)   was   irradiated   with   long-­‐wave   UV   light   in   the  presence   of   a   trithiocarbonate   iniferter   to   produce   ultrahigh   molecular   weight   (UHMW)  poly(DMA).  Turning  off  the  UV  light  stopped  the  polymerization,  which  could  be  reinitiated  by  turning   on   the   light   source,   demonstrating   the   rapid   reversible   termination   between   the  propagating   chain-­‐end   and   sulfur-­‐centered   iniferter   radical.   The   polymerization   of   DMA   to  UHMW   (Mn,SEC   1.26   ´   106   g/mol)   maintains   a   similar   polymerization   rate   through   activation  cycles.   Size-­‐exclusion   chromatography   (SEC)   traces   shift   to   shorter   elution   times   and   higher  molecular  weights  throughout  the  polymerization  was  the  SEC  traces  remain  monomodal.  The  predicted  molecular  weights  (Mn,  theory)  closely  matches  measured  values  (Mn,  SEC)  as  monomer  conversion  increases,  while  molecular  weight  distributions  (Ð)  remained  low.    

 

     

 Figure  S5.  a)  The  trithiocarbonate  iniferter  shows  an  increased  extinction  coefficient  (lmax  310  nm)  compared  to  b)  the  xanthate  iniferter  (lmax  281  nm)  in  water.  Absorbance  measurements  were   conducted   with   150   μL   of   sample   on   clear   96-­‐well   microplates   (Greiner).   Calibration  curves  and  path  length  correction  were  constructed  using  the  integrated  SoftMax  Pro  software.  

 

 Figure   S6.   N,N-­‐Dimethylacrylamide   (DMA)   was   irradiated   with   long-­‐wave   UV   light   in   the  presence   of   a   xanthate   iniferter   to   produce   ultrahigh  molecular  weight   (UHMW)   poly(DMA).  The  polymerization  of  DMA  to  UHMW  (Mn,SEC  1.30  ´  106  g/mol)  displays  near-­‐linear  pseudo-­‐first  order  kinetics,  indicating  a  constant  radical  concentration  up  to  93%  monomer  conversion.  Size-­‐exclusion   chromatography   (SEC)   traces   shift   to   shorter   elution   times   and   higher   molecular  weights  throughout  the  polymerization  was  the  SEC  traces  remain  monomodal.  The  predicted  molecular  weights   (Mn,  theory)   closely  match  measured  values   (Mn,  SEC)   as  monomer   conversion  increases,  while  molecular  weight  distributions  (Ð)  remained  low.  

 

 

 Figure   S7.   N,N-­‐Dimethylacrylamide   (DMA)   was   irradiated   with   long-­‐wave   UV   light   in   the  presence   of   a   xanthate   iniferter   to   produce   ultrahigh  molecular  weight   (UHMW)   poly(DMA).  The  polymerization  of  DMA  to  UHMW  (Mn,SEC  2.96  ´  106  g/mol)  displays  near-­‐linear  pseudo-­‐first  order  kinetics,  indicating  a  constant  radical  concentration  up  to  93%  monomer  conversion.  Size-­‐exclusion   chromatography   (SEC)   traces   shift   to   shorter   elution   times   and   higher   molecular  weights  throughout  the  polymerization  was  the  SEC  traces  remain  monomodal.  The  predicted  molecular  weights   (Mn,  theory)   closely  match  measured  values   (Mn,  SEC)   as  monomer   conversion  increases,  while  molecular  weight  distributions  (Ð)  remained  low.  

 

 Figure   S8.   N,N-­‐Dimethylacrylamide   (DMA)   was   irradiated   with   long-­‐wave   UV   light   in   the  presence   of   a   xanthate   iniferter   to   produce   ultrahigh  molecular  weight   (UHMW)   poly(DMA).  The  polymerization  of  DMA  to  UHMW  (Mn,SEC  5.20  ´  106  g/mol)  displays  near-­‐linear  pseudo-­‐first  order  kinetics,  indicating  a  constant  radical  concentration  up  to  95%  monomer  conversion.  Size-­‐exclusion   chromatography   (SEC)   traces   shift   to   shorter   elution   times   and   higher   molecular  weights  throughout  the  polymerization  was  the  SEC  traces  remain  monomodal.  The  predicted  molecular  weights   (Mn,  theory)   closely  match  measured  values   (Mn,  SEC)   as  monomer   conversion  increases,  while  molecular  weight  distributions  (Ð)  remained  low.  

 

 Figure   S9.   N,N-­‐Dimethylacrylamide   (DMA)   was   irradiated   with   long-­‐wave   UV   light   in   the  presence   of   a   xanthate   iniferter   to   produce   ultrahigh  molecular  weight   (UHMW)   poly(DMA).  The  polymerization  of  DMA  to  UHMW  (Mn,SEC  8.57  ´  106  g/mol)  displays  near-­‐linear  pseudo-­‐first  order  kinetics,  indicating  a  constant  radical  concentration  up  to  89%  monomer  conversion.  Size-­‐exclusion   chromatography   (SEC)   traces   shift   to   shorter   elution   times   and   higher   molecular  weights  throughout  the  polymerization  was  the  SEC  traces  remain  monomodal.  The  predicted  molecular  weights   (Mn,  theory)   closely  match  measured  values   (Mn,  SEC)   as  monomer   conversion  increases,  while  molecular  weight  distributions  (Ð)  remained  low.  

 

   Figure   S10.   N,N-­‐Dimethylacrylamide   (DMA)   was   irradiated   by   sunlight   in   the   presence   of   a  trithiocarbonate   iniferter   to   produce   ultrahigh   molecular   weight   (UHMW)   poly(DMA).   The  polymerization   of   DMA   to   UHMW   (Mn,SEC   1.60  ´   106   g/mol)   displays   near-­‐linear   pseudo-­‐first  order  kinetics,  indicating  a  constant  radical  concentration  up  to  62%  monomer  conversion.  Size-­‐exclusion   chromatography   (SEC)   traces   shift   to   shorter   elution   times   and   higher   molecular  weights  throughout  the  polymerization  was  the  SEC  traces  remain  monomodal.  The  predicted  molecular  weights   (Mn,  theory)   closely  match  measured  values   (Mn,  SEC)   as  monomer   conversion  increases,  while  molecular  weight  distributions  (Ð)  remained  low.    

 

 Figure   S11.   The   exothermicity   of   the   UHMW   DMA   polymerization   via   a   xanthate   or  trithiocarbonate   iniferter   was   recorded   with   an   external   thermocouple.   Within   5   min,   the  xanthate   initiated   polymerization   solution   temperature   rapidly   increased   by   +11.7   °C,  eventually  reaching  a  peak  temperature  of  38.0  °C  before  plateauing  to  ~36  °C.  However,  the  trithiocarbonate  showed  a  delayed  and  much  less  pronounced  exotherm,  reaching  a  constant  temperature  near  37  °C.  These  polymerizations  are  compared  to  an  aqueous  monomer  solution  without  iniferter.  

 

 Figure  S12.  Kinetic  plots  for  polymerizations  of  DMA  in  the  presence  and  absence  of  iniferter.  UV   irradiation   of   DMA   in   the   absence   of   iniferter   results   in   slow,   adventitious   background  initiation;   however,   this   result   has   little   impact   on   photoiniferter-­‐mediated   polymerizations.  The  slow   iniferter-­‐free  polymerization  resulted   in  an  Mn  of  2.04  ´  106  g/mol  and  Ð  of  1.16  at  30%  conversion   in  8  h.   Importantly,  during   the  uncontrolled   iniferter-­‐free  polymerization   the  molecular   weight   was   constant   regardless   of   monomer   conversion.   Xanthate   and  trithiocarbonate   mediated   polymerizations   targeted   similar   degrees   of   polymerizations   with  [DMA]:[Iniferter]   =   50,000:1.   The   xanthate   and   trithiocarbonate   mediated   polymerizations  reached  near  quantitative  conversion  in  1  and  8  h,  respectively  (Table  1  entry  7  and  3).    

 

Figure  S13.  Kinetic  plots  for  polymerizations  of  DMA  with  various  concentrations  of  Xanthate.  Increasing   [DMA]:[Xanthate]   ratios   and   degrees   of   polymerization   lead   to   slower  polymerization  rates.        [1]   Wang  R.;  McCormick,  C.  L;  Lowe,  A.  B.  Synthesis  and  Evaluation  of  New  Dicarboxylic  Acid  

Functional  Trithiocarbonates:   RAFT  Synthesis  of  Telechelic  Poly(n-­‐butyl  acrylate)s.  Macromolecules  2005,  38  (23),  9518–9525.  

[2]   Smulders  W.;  Monteiro,  M.  J.  Seeded  Emulsion  Polymerization  of  Block  Copolymer  Core−Shell  Nanoparticles  with  Controlled  Particle  Size  and  Molecular  Weight  Distribution  Using  Xanthate-­‐Based  RAFT  Polymerization.  Macromolecules  2004,  37  (12),  4474-­‐4483.  

       


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