Surface Modification of Polyvinyl Chloride Sheets via Growth of Hydrophilic Polymer Brushes

Abstract

Poly(N,N-dimethylacrylamide) (PDMA) brushes were successfully grown from polyvinyl chloride (uPVC) sheets via well-controlled surface-initiated atom transfer radical polymerization (SI−ATRP). An ATRP initiator containing a chloropropionate moiety was chemically tethered onto the surface of PVC via a novel wet chemical modification. Negatively charged sulfate groups were introduced to facilitate polymerization. By incorporating a chemically cleavable group into the initiator, molecular weight, polydispersity and graft density of a series of PDMA brushes synthesized on the flat surface were unambiguously characterized for the first time by gel permeation chromatography. ATR−FTIR, contact angle, SEM and AFM were used to characterize the PDMA grafted surfaces. Reaction conditions such as monomer concentration, reaction time, copper(II) concentration and salt additives were varied to systematically investigate their effects on molecular weight and graft density of the PDMA grafted from PVC. Molecular weights of grafted PDMA brushes varied from ca. 20 000 to 2 170 000 Da, while graft density ranged from 0.08 to 1.13 chains/nm2. Polydispersity of grafted PDMA brushes was controlled between 1.20 and 1.60 by Cu(II) complex addition. Kinetic studies revealed that the surface initiation was a slow process and graft density increased during the reaction. The brush uniformity increased with increasing reaction time. Reinitiation of the obtained PDMA brushes was demonstrated, suggesting that the polymerization is “living”. The successful growth of a PDMA-b-poly(N-isopropylacrylamide) (PNIPAM) copolymer brush was verified by GPC and AFM.

Choline phosphate functionalized cellulose membrane: A potential hemostatic dressing based on a unique bioadhesion mechanism

“…It is reported that the higher the monomer concentration, the higher the molecular weight of grafted polymer for SI-ATRP [38]. In order to investigate the effect of molecular Table 2) monomer concentration at room temperature for 24 h for a given copper catalyst concentration.…”

Inhibitory Effect of Hydrophilic Polymer Brushes on Surface‐Induced Platelet Activation and Adhesion

“…The experimental details are published elsewhere. [25] Briefly, primary amine groups were first introduced onto an uPVC surface by wet chemical modification with 4-aminothiophenol, followed by coupling of hydroxy groups by a ring opening reaction of amine groups with glycidol. The ATRP initiator was then covalently coupled to the surface by an ester linkage.…”

“…By changing the monomer concentration (1 to 10%), catalyst concentration, and polymerization time various molecular weights, polydispersities, and graft densities can be obtained. [25] Characterization of PDMA Brushes on PVC Surfaces…”

“…Characteristic peaks for amide I and II, which belong to grafted PDMA chains, were observed at 1 630 and 1 540 cm À1 , respectively. The graft density and molecular weight of the PDMA chains were analyzed after cleaving them from the surface [25] and the GPC profiles of the cleaved chains ( Figure 1S, Supporting Information) show monomodal distributions. For the study described here, we selected a group of PDMA brush samples with different molecular weights and graft densities ( Table 1 and 2).…”

“…Polydispersities (M w =M n ) ranged from 1.2 to 1.8, which is relatively low considering the nature of surfaceinitiated polymerization. [25] The growth of PDMA brushes from uPVC surfaces significantly changed their surface characteristics. For example, the water contact angle of PDMA-grafted uPVC surfaces decreased sharply (Table 1 and 2) compared to bare uPVC (94.58) and an ATRP initiator-coupled uPVC surface (abbreviated as uPVC-AI, 92.78).…”