How can I use merge to cbind two dataframes

Suppose I have two dataframes:

df1 <- data.frame(matrix(rnorm(10*10),ncol=10))
df2 <- data.frame(matrix(rnorm(10*10),ncol=10))
colnames(df1) <- 1:10
colnames(df2) <- 11:20

How do I use merge to cbind these (I already know about cbind but I am interested in the application of merge here).