Consider the following figure

F

No of segments = N

X

One end of a polymer chain is attached to a rigid support, while its

other end is being pulled by a force F. We want find an expression

for F in terms of the length of the chain X.

a. The partition function of the chain is,

Fa

Ansinh

Z(= e KBT)

KBT)

Fa

kgT

Where, a is segment length, known as Kuhn length, N is the

total number of segments and F is the applied force.

b. Calculate the entropy of the chain.

c. Calculate the end-to-end distance X as a function of the applied

force