A sample of polyethylene has molar mass

PHYSICS · Multi-part · Fermi University Physics · Condensed Matter, Materials & Soft Matter · Soft condensed matter · Soft condensed matter

Condensed Matter Physics, Ch Soft matter: when entropy, not bonding, sets the structure

Problem

A sample of polyethylene has molar mass 560 kg mol−1560\,\mathrm{kg\,mol^{-1}}, built from CH2\mathrm{CH_2} links of molar mass 14 g mol−114\,\mathrm{g\,mol^{-1}} each. Treating each link as an idealised freely jointed segment of length bmon=0.154 nmb_{\rm mon}=0.154\,\mathrm{nm} (the carbon-carbon bond length), find ((a)) the number of links NmonN_{\rm mon}, ((b)) the coiled size ReeR_{\rm ee}, ((c)) the contour length, and ((d)) the ratio of the two.

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