Solvent and temperature influences on polystyrene unperturbed dimensions

Branching Analysis of Comb‐Shaped Polystyrene with Long Chain Branches

“…The lines are the least square fit of the linear PS data and the MW dependences of R g and [η] of the linear PS are R g = 2.36 × 10 −2 M 0.51 and [η] = 6.91 × 10 −4 M 0.50 . The MW exponents of R g versus MW and [η] versus MW for linear PS confirm that the experimental condition was very close to a theta condition and the R g and [η] values are in good agreement with the literature data: R g in diethyl malonate at 35 °C, [η] = 8.15 × 10 −4 M 0.492 in diethyl malonate at 34.5 °C, or [η] = 7.18 × 10 −4 M 0.5 in diethyl malonate at 34.2 °C . The R g and [η] values of comb‐shaped PS are lower than the linear PS at the same MW due to the chain contraction upon branching as we also observed in a good solvent (Figure ).…”

“…Figure a shows the IC‐LS chromatograms of fractionated 140k–70k PS combs with varying number of branches in diethyl malonate. The theta temperature of PS in diethyl malonate was reported around 35 °C . However, the IC elution at the theta temperature is impossible since PS is adsorbed to the stationary phase too strongly to elute out of the column.…”

Discriminating Among Co‐monomer Sequence Distributions in Random Copolymers Using Interaction Chromatography

“…The u temperature (Q) for PS in CUD has been established previously to be 32.8 8C. [10][11][12] Hence, while bromination of PS at temperatures above Q produced PBr x S RCPs with a random distribution of the 4-BrS segments (r-PBr x S), PBr x S copolymers formed at temperatures below Q possess more blocky distribution of 4-BrS (bPBr x S). A series of PS homopolymers (M n ¼ 30 kDa) was brominated at temperatures ranging from 22.0 to 43.6 8C producing PBr x S whose degree of bromination ranged from 28.0 to 38.5 mol-%, respectively.…”

Facile Method of Controlling Monomer Sequence Distributions in Random Copolymers

“…[24] Due to their structural resemblance, 1-chlorodecane (CD, h = 6.6°C), 1-chloroundecane (CUD, h = 32.8°C), and 1-chlorododecane (CDD, h = 58.6°C) have very similar dipole moments. [25][26][27] Hence, at a given temperature the kinetics of bromination is expected to be similar for all three solvents. Depending on the solvent and the solution temperature, the PS coil can either be expanded (T > h), unperturbed (T = h), or collapsed (T < h).…”