PMID- 37637307
OWN - NLM
STAT- PubMed-not-MEDLINE
LR  - 20231002
IS  - 0024-9297 (Print)
IS  - 1520-5835 (Electronic)
IS  - 0024-9297 (Linking)
VI  - 56
IP  - 16
DP  - 2023 Aug 22
TI  - Continuous-Flow Laboratory SAXS for In Situ Determination of the Impact of 
      Hydrophilic Block Length on Spherical Nano-Object Formation during 
      Polymerization-Induced Self-Assembly.
PG  - 6426-6435
LID - 10.1021/acs.macromol.3c00585 [doi]
AB  - In situ small-angle X-ray scattering (SAXS) is a powerful technique for 
      characterizing block-copolymer nano-object formation during 
      polymerization-induced self-assembly. To work effectively in situ, it requires 
      high intensity X-rays which enable the short acquisition times required for 
      real-time measurements. However, routine access to synchrotron X-ray sources is 
      expensive and highly competitive. Flow reactors provide an opportunity to obtain 
      temporal resolution by operating at a consistent flow rate. Here, we equip a 
      flow-reactor with an X-ray transparent flow-cell at the outlet which facilitates 
      the use of a low-flux laboratory SAXS instrument for in situ monitoring. The 
      formation and morphological evolution of spherical block copolymer nano-objects 
      was characterized during reversible addition fragmentation chain transfer 
      polymerization of diacetone acrylamide in the presence of a series of 
      poly(dimethylacrylamide) (PDMAm) macromolecular chain transfer agents with 
      varying degrees of polymerization. SAXS analysis indicated that during the 
      polymerization, highly solvated, loosely defined aggregates form after 
      approximately 100 s, followed by expulsion of solvent to form well-defined 
      spherical particles with PDAAm cores and PDMAm stabilizer chains, which then grow 
      as the polymerization proceeds. Analysis also indicates that the aggregation 
      number (N(agg)) increases during the reaction, likely due to collisions between 
      swollen, growing nanoparticles. In situ SAXS conducted on PISA syntheses using 
      different PDMAm DPs indicated a varying conformation of the chains in the 
      particle cores, from collapsed chains for PDMAm(47) to extended chains for 
      PDMAm(143). At high conversion, the final N(agg) decreased as a function of 
      increasing PDMAm DP, indicating increased steric stabilization afforded by the 
      longer chains which is reflected by a decrease in both core diameter (from SAXS) 
      and hydrodynamic diameter (from DLS) for a constant core DP of 400.
CI  - (c) 2023 The Authors. Published by American Chemical Society.
FAU - Guild, Jonathan D
AU  - Guild JD
AD  - School of Chemical and Processing Engineering, University of Leeds, Woodhouse, 
      Leeds LS2 9JT, U.K.
FAU - Knox, Stephen T
AU  - Knox ST
AUID- ORCID: 0000-0001-5276-0085
AD  - School of Chemical and Processing Engineering, University of Leeds, Woodhouse, 
      Leeds LS2 9JT, U.K.
FAU - Burholt, Sam B
AU  - Burholt SB
AD  - Diamond House, Harwell Science and Innovation Campus, Diamond Light Source, 
      Didcot OX11 0DE, U.K.
FAU - Hilton, Eleanor M
AU  - Hilton EM
AD  - School of Chemical and Processing Engineering, University of Leeds, Woodhouse, 
      Leeds LS2 9JT, U.K.
FAU - Terrill, Nicholas J
AU  - Terrill NJ
AD  - Diamond House, Harwell Science and Innovation Campus, Diamond Light Source, 
      Didcot OX11 0DE, U.K.
FAU - Schroeder, Sven L M
AU  - Schroeder SLM
AUID- ORCID: 0000-0002-4232-5378
AD  - School of Chemical and Processing Engineering, University of Leeds, Woodhouse, 
      Leeds LS2 9JT, U.K.
FAU - Warren, Nicholas J
AU  - Warren NJ
AUID- ORCID: 0000-0002-8298-1417
AD  - School of Chemical and Processing Engineering, University of Leeds, Woodhouse, 
      Leeds LS2 9JT, U.K.
LA  - eng
PT  - Journal Article
DEP - 20230804
PL  - United States
TA  - Macromolecules
JT  - Macromolecules
JID - 0365316
EIN - Macromolecules. 2023 Sep 08;56(18):7651. PMID: 37781213
PMC - PMC10448749
COIS- The authors declare no competing financial interest.
EDAT- 2023/08/28 06:41
MHDA- 2023/08/28 06:42
PMCR- 2023/08/24
CRDT- 2023/08/28 04:47
PHST- 2023/04/04 00:00 [received]
PHST- 2023/07/20 00:00 [revised]
PHST- 2023/08/28 06:42 [medline]
PHST- 2023/08/28 06:41 [pubmed]
PHST- 2023/08/28 04:47 [entrez]
PHST- 2023/08/24 00:00 [pmc-release]
AID - 10.1021/acs.macromol.3c00585 [doi]
PST - epublish
SO  - Macromolecules. 2023 Aug 4;56(16):6426-6435. doi: 10.1021/acs.macromol.3c00585. 
      eCollection 2023 Aug 22.