Lecture 8

Question 1

LCST (lower critical solution temperature)

Answer 1

below a certain temp, polymer is soluble, when heated polymer precipitates

Question 2

UCST(upper critical solution temperature)

Answer 2

above a certain temp, polymer is soluble, precipitates upon cooling

Question 3

in scattering experiments, we need to have _____ to see the species

Answer 3

contrast

Question 4

polarization

Answer 4

direction of electric field oscillation

Question 5

how does light scattering work?

Answer 5

light causes charges to polarize and oscillating charges radiate light

Question 6

SLS vs DLS

Answer 6

SLS is slow, uses Rg and molar mass
DLS is fast, uses translational diffusion coeff, and Rh

Question 7

SLS set up

Answer 7

collect signals of scattered light measured at different angles

Question 8

T/F viscometry is a cheap way to assess polymer MW and conformations

Answer 8

TRUE

Question 9

traditional SEC assumptions

Answer 9

sample has:
- same conformation as standards
- same density as standards
- does not interact with column packing