Figure 1.

Polymer library construction and characterization. (A) Generalized structure for PEG-b-(DMAEMA-co-BMA) polymers. (B) The composition library consists of six polymers, ranging from 0% BMA to 75% BMA. Each polymer is composed of a 5000 g/mol PEG block and a second random copolymer block with an average MW of approximately 22 000 g/mol. (C) The MW library consists of seven polymers. Each contains a 5000 g/mol PEG block and a second random copolymer block composed of an approximately 50:50 ratio of DMAEMA to BMA monomers and with MW ranging from 11 300 to 47 500 g/mol. (D) Gel permeation chromatography traces show that all polymers in the composition library have similar, low polydispersity and approximately equivalent MW. (E) Gel permeation chromatography traces show that all the candidates in the MW library have well-controlled polydispersity and have a wide range of MW values. (F) Plot of log acid dissociation constant (pK_a) shows that composition significantly impacts pK_a; 75B is omitted due to insolubility under assay conditions; line of best fit: pK_a = 7.36–0.019 x (x expressed in percent BMA). (G) Plot of log acid dissociation constant (pK_a shows that MW has only a modest effect on pK_a; line of best fit: pK_a = 6.71 – (9.6 × 10⁻⁶) x (x expressed in grams per mole).